Dec 3, 2018

Acropora Facts You Probably Didn't Know

Acropora coloration - it’s all about the symbionts

A beautiful and rewarding relationship between stony corals and single celled dinoflagellate algae began sometime in the late Triassic over 200 million years ago. Corals formerly relied solely on food capture with their polyps for energy, making them slow growers. Adopting these algae cells called Zooxanthellae allowed corals to utilize both photosynthesis and food capture for faster reef-building growth, which led to the creation and evolution of our now irreplaceable, essential reef ecosystems. Acropora corals first appeared during the Eocene Epoch 37 to 54 million years ago, the beginning of our story.  

Acropora coloration is in part due to these symbiotic zooxanthellae, which are plant-like cells, that live within their tissues. The coral produces CO2 and H2O, and the zooxanthellae use these for photosynthesis which in turn feeds the coral polyps. In captivity, dark brown or green Acropora are usually a result of overfeeding the zooxanthellae organic matter with high concentrations of nitrate and phosphate in the tank water. Excessively bright lighting or high temperatures can cause “bleaching,” which is when the zooxanthellae leave the coral, making its tissue nearly transparent and exposing the white skeleton beneath.

It isn’t fully understood why corals produce fluorescent coloration which is visible under actinic lighting in aquariums. UV light found in some LED lights and metal halide lights can bring out the protective fluorescent blue, purple, and pink pigments of shallow-water Acropora. Deeper water corals may produce fluorescent pigments to provide more light to their photosynthetic symbionts.

In addition to Zooxanthellae, there are other symbionts working with Acropora to process nutrients and influence their coloration. Little known fungus-like protists called Thraustochytrids may be responsible for some of the fluorescent proteins found in Acropora and other corals.

It’s almost impossible to identify captive grown Acropora

Identification of captive grown Acropora corals is difficult and in most cases, futile. Even experts who have studied wild Acropora for a lifetime can’t identify a captive Acropora with any certainty. We hobbyists have managed to change the coloration and morphology of our Acropora corals using unnatural conditions, making them nearly unrecognizable. This difficulty is compounded when faced with identifying tiny frags or small colonies. When you see an Acropora identified by scientific name in the hobby, chances are it’s just an educated guess.

The fastest growing Acropora are staghorns

The general consensus among aquarists is that the Green Slimer Acropora yongei is the fastest growing Acropora coral in captivity today. Acropora yongei branches on the Great Barrier Reef have been recorded growing as much as 4.3” during a 15 week summer. That’s more than an inch a month!

Image found at [1]. Created by NOAA's Florida Keys National Marine Sanctuary

Acropora palmata form the largest Acropora colonies

The largest Acropora species is the rare and endangered Acropora palmata from the Caribbean, which typically grows to over 13 feet across, 6.5 feet high, and with a base of 1.3 feet thick.

Acropora corals are easy to frag

Despite being considered one of the most difficult corals to keep in captivity, Acropora corals are surprisingly easy to frag. Thin branches can be carefully broken with your hand, but thicker branches should be cut with a pair of stainless steel “bone” or coral cutters. If you have a coral wet saw, you can frag large colonies quickly.

Small frags can be superglued to plugs. Frags will stick better if the plug is dry. If you want branches to be glued to plugs in an upright position, use plugs with holes drilled in the center that are slightly larger in diameter than the branch. It is also possible to glue a branch horizontally onto a flat plug. Hold the coral for about 30 seconds to set the glue, then carefully place the plug in a frag rack until it cures. Larger frags may need epoxy and superglue to secure them into a hole in live rock. New frags can be traded or sold when the flesh starts to encrust onto the plug.

Big R Corals Walt Disney Acropora tenuis photo credit Coralust

Pedigreed Acro frags can cost more than a month's mortgage

One of the most sought after and expensive Acro frags is the Jason Fox Homewrecker Acro frag retails for $999.99. Many hobbyists were skeptical of its extremely bright coloration in photos, some calling it “Photoshopped.” Those who saw the frags in person at MACNA 2017 in New Orleans will attest to the accuracy of photos of this unbelievable coral.

A modestly expensive and sought after Acropora frag is Mike Biggar’s of Big R Corals Walt Disney Tenuis Acropora frag. A ¾” frag of this blue and pink A. tenuis with yellow polyps retails for $199.99.

Possibly the most expensive Acro frag today is a ½” RR’s Bleeding Avenger Acro which retails on Cornbred’s site for $1999.99. Two. Thousand. For a half inch.

Those on a budget should not discount the value of the $5 brown Acropora frags in the local fish store’s sale bin. With some TLC and proper conditions, that tiny brown frag could regain bright coloration and eventually become a cherished show piece.

Acropora efflorescens - an unusual growth form for an Acropora

There’s more to Acropora than branching

We tend to think of Acropora corals as being “branchy,” but the nearly 150 different species of Acropora have 7 distinct growth forms - tables/plates, staghorn, bushy, massive, bottlebrush, corymbose, and digitate. Some of the most sought after are the deepwater bottlebrush forms like Acropora echinata and the tabling forms like Acropora hyacinthus.
Digitate Acropora coral

Acropora can share and adopt new Zooxanthellae

The Shedd Aquarium in Chicago reported that their Caribbean Acropora corals were adopting Zooxanthellae from the Pacific species. The spawn collected A. palmata frags they housed in the same system with Pacific Acropora started sporting new purple polyps, and DNA test results proved the Zooxanthellae were Pacific in origin. Zookeepers and public aquarists lament the delicate nature and difficulty of A. palmata and cervicornis. Could introducing Pacific Zooxanthellae to Caribbean Acropora make the corals hardier?

Acropora corals are unique, important ecosystems

Acropora are called “reef-building” corals because they form hard skeletons that create important habitats for countless reef fish and invertebrates and nurseries for reef fish and large open water fish fry. One billion people world wide depend on coral reefs economically. A collapse of coral reef ecosystems would have devastating consequences, and its effects would be felt by every living human.

Even small colonies of Acropora corals can host many varieties of species. Tetralia and Trapezia crabs are symbiotic defenders of Acropora corals, feeding on coral mucous and chasing away predators. Polychaete worms and feather dusters, barnacles, crabs, shrimps, commensal shell-less hermit crabs, tiny fish like coral gobies and coral crouchers, copepods, amphipods, flatworms, sponges, and tunicates have all been known to make their homes either inside or underneath the safety of Acropora colonies. Dr. Ronald Shimek reports in the July/August 2018 issue of CORAL magazine that in a single large Acropora hyacinthus colony is likely to house several thousand species of symbionts.

Acropora in the wild need our help

American Acropora palmata and Acropora cervicornis were once some of the most common stony corals in their respective ranges in the Caribbean, Florida keys, Gulf of Mexico and Bahamas, but populations have declined by estimates of up to 95% in the last 30 years. Their rapid decline has been attributed to climate change and pollution, which makes the Acropora susceptible to other threats like disease. Climate change also increases coral damaging hurricane frequency and severity and higher ocean surface temperatures which contribute to coral bleaching events.

Serratia marcescens, a pathogenic, gram negative bacteria commonly found in the gastrointestinal tract and other mucosal surfaces of humans, causes a disease specific to A. palmata called white pox disease. Other diseases that plague A. palmata and A. cervicornis are Black band disease and White band disease which can also decimate entire populations quickly. Black band disease is caused by Cyanobacteria and bacteria infecting coral tissue. White band disease is not well studied, but experts believe there are many types that may be caused by several species of bacteria such as Vibrio harveyi and/or ciliate parasite Philaster lucinda.

All Acropora are listed under CITES appendix II, and many are threatened. Other species of Acropora that are endangered according to the IUCN red list are A. rudis and A. suharsoni.

There is little hope for the recovery of American Acropora species, but organizations like the Coral Restoration Foundation are not ready to give up. Ken Nedimyer and his team frag, grow, and redistribute healthy Elkhorn corals. They use innovative techniques like hanging frags on elevated trees to prevent them from being smothered by sediment or exposed to pathogens. If you’d like to help out, please visit their website

Veron Corals of the World Volume 1

Sep 13, 2018


The Flashiest of Wrasses: The McCosker’s Wrasse!

My parents set up a 30 gallon reef tank about 6 months ago, and they were looking for one perfect fish for their tank. I suggested clownfish, but they think those are are boring. I showed them dozens of easy, peaceful, small reef-safe fish, and they fell in love with the McCosker’s wrasse.

Paracheilinus Wrasse or McCosker’s Flasher Wrasse do best in 55 gallon or larger aquariums, but we planned on them being the only fish in the 30 gallon tank. My parents bought a male/female pair at our local fish store on an impulse, worried someone else would buy them.

I stopped by their house to help acclimate the fish, and realized they had not yet installed the net around the aquarium’s canopy to prevent the fish from jumping. I knew from previous experiences with this fish, it is imperative to have a fully enclosed top. These fish can jump high, and they can jump accurately. If you have even a tiny, unnoticeable gap between your net and a U-tube or heater’s wire, they’ll find a way to get through it.

Luckily, they had some fine mesh netting in the basement, so we were able to cut it and staple it to the canopy temporarily while the fish drip acclimated.

They were worried that the fish looked dead in the acclimation bucket, but I reassured them that it is normal for this type of wrasse to lie down and appear mottled for camouflage. It’s also common for them to do this in small containers, but they recover quickly when given room to swim. Don’t be alarmed if you see your fish lying on the bottom of the tank at night covered in slime, since these fish form mucous cocoons at night to sleep in.

I warned them that the fish might hide for a while, but our LFS did a great job of conditioning them. They were out the next morning, eating frozen mysis shrimp and brine shrimp. We plan to also add some tasty, nutritious oyster eggs and copepods to their diet to help provide a more complete nutrition, besides who wants to eat the same thing everyday?

I recommend quarantining all new fish. This species tends to suffer from Monogenean Flukes, which are microscopic or tiny clear flat worms that crawl on the skin and eyes of the fish, eating the mucous and causing damage. A short freshwater dip (make sure to match the pH to your tank) can remove most of the flukes, and treatment with Praziquantel in the quarantine tank can remove any leftover flukes.

It’s also a great idea to treat these fish for Cryptocaryon, aka ICH, before they are added to your display tank with other fish. They don’t tolerate Copper or Chloroquine Diphosphate well, so use the tank transfer method instead. If you notice your fish losing weight despite eating well, treat for internal parasites by soaking their food in Metronidazole and Prazi-Pro.

These fish are always beautiful, but when they display their “nuptial colors,” they are downright electric. The Males will display for females, other males, or mirrors. The male will flare all of his fins as large as possible while doing an erratic back and forth dance. The blue lines on his body appear to glow from the inside. The more females you have per one male, the more he will flash and display. It’s best to have just one male per tank, but some experienced keepers have multiple males in large aquariums.

articles and photos by Felicia McCaulley

Aug 15, 2018

Aqua Illumination Prime Review and Unicorn Reef Bowl Update

A lot has been happening with the 8.5 gallon Unicorn Reef Bowl lately. I got a few new frags from Reef-a-Palooza 2018 and TSM Corals in New Jersey.

Unicorn Reef Bowl with AI Prime
I also got new Aqua Illumination Prime from Marine Depot to replace my ABI Tuna Blue light, and I couldn't be happier with it. I still use the ABI bulbs in other tanks, and they are trusty and true, but I enjoy the programmability, customizability, and rich colors the AI Prime offers. The ABI is a good, inexpensive bulb that has faithfully grown my coral for a couple years now, b ut the AI Prime is in an entirely different league with its controls and sleek, aesthetic design.

The AI Prime is controlled by an app that I easily downloaded to my Samsung phone. The app controls are so intuitive, this low-tech 35 year old lady didn't even have to read any directions. The controls just make sense. You can program each of the 7 colors down to the percent. The colors are absolutely stunning and there are endless combinations. The app has a handy acclimation mode so you can slowly get your corals used to the new light. You should also use acclimation mode when you get new coral. My favorite feature on the app is the weather. You can program clouds and lightning storms to happen each day, and you can even choose the probability and intensity of the storms.

I get a lot of questions about what is the "right" percentage for each color. Stick with your typical 6500K, 10000K, 14000K, or 20000K spectrum (depending on the look you like and the types of corals you have) if you're a beginner with this light. Go to Control > Manual, then tap the "semicircles" icon at the top right corner. This will allow you to adjust the Kelvin rating and intensity. Choose the Kelvin and intensity you want, then click the "sliders" icon at the top right. Remember the percentages of each color. Now go to Control > Auto > Easy Setup and input those percentages. Set your sunrise and sunset and the ramp time for an hour to simulate gradual sunrise and sunset. If you're still unsure and want to download settings that have been designed and used by expert reefers, visit

Here you can see a video of the ramp up from sunrise to sunset. This is what a day in the life of my tank would look like on hyperspeed if these were the settings I chose.

I also got a new toy to help me photograph the reef bowl with my camera phone without having to manipulate the colors in post processing. The Polyp Lab Coral View lens for Smartphone and Tablet kit comes with three lenses - 15,000K, 20,000K, and a 10x macro lens, plus a holder that clips onto your phone. The lenses are stackable, so if you want to use the orange lens and the macro lens at the same time, you can do that! The kit also comes with a cleaning cloth, cases for each lens, and a sturdy box for storage. I've been taking this kit with me everywhere I go just in case I need to quickly and easily photograph a tank (which usually happens everywhere I go!)

You may notice another huge change to the Unicorn Reef Bowl - my favorite Montipora setosa that my friend Ryan Pettit gave me years ago has died. It started to STN (slow tissue necrosis) about 6 months ago, and I just could not save it to matter what I did. None of the other corals, even the Montiporas, were affected.Sometimes we never know what causes corals to die for seemingly no reason. The last bit of flesh finally disappeared recently, and I removed the sad skeleton. It was the hardest coral loss I've ever experienced. I could replace it with another setosa, but it wouldn't be the same. That coral had so much history. I remember driving to my long-time friend Ryan's house in 2014 and enjoying a rare visit with him and his family, as he excitedly chose and cut corals to selflessly give to me. When I moved back to Pennsylvania, I took this coral with me and put it in my friend's tank for safekeeping. When I was ready, he gave me a piece of it for my reef vase, where it flourished and grew to the size of my hand.

January 2018

June 2017 

November 2017
What's interesting is that it always grew in a weird, nearly perfect ring around a barren center. It finally covered the center in November 2017, but when it started to die, the STN started right there in the center. A friend suggested I cut the center out and hope it would recover, but that didn't help. I tried cutting healthy pieces off the edge, but those died, too. I even put some of those healthy edge pieces in tanks of various friends hoping it would revive in their tanks. They died.

The corals are doing great now in the Unicorn Reef Bowl with the new AI Prime light. I also got a new wavemaker and a generic eBay Sun Sun canister filter that is helping to improve conditions. I like the Sun Sun, but I think eventually I'll upgrade to an Eheim filter just for quality and longevity.

Blue Tenuis frag from TSM Corals

Blue Tenuis in my bowl

Bubblegum Digitata from Mo's corals

My 4 year old acclimating hermit crabs

Acropora nasuta from TSM corals

Top down view with ABI bulb

Full tank shot Unicorn Reef Bowl AI Prime evening

AI Prime daytime Unicorn Reef Bowl

Aug 13, 2018

BCAS talk Sept 2018 - Seahorse Keeping: IT'S NOT THAT HARD

Please join Bucks County Aquarium Society and Felicia McCaulley on September 6th, 2018 at 7:30pm at the Churchville Nature Center to discuss myths surrounding seahorse keeping and why they're not as fragile as we think!

I will cover topics that will ensure seahorse keeping success and make it easy for you.

Stop by the nearby Fish Factory in Bensalem, PA to pick up your very own Felicia's Saddled Seahorses, born and raised right here in Pennsylvania. They're currently about one year old and very healthy and hardy. There are some yellow, orange, rusty brown, and grey colored seahorses (they change color based on their surroundings).

Jun 19, 2018

Secrets For Success: Rules You Should Follow To Keep Your Seahorse Aquarium Thriving


A friendly seahorse hitched on her favorite human’s hand.

So you’re interested in seahorses? It’s easy to see why!

Seahorses are some of the most interesting and unique fish on the planet. They make great pets and can become quite tame. They know who their humans are and will interact with you in ways other fish can not. They can learn to eat from your hand or even hitch on your fingers. You may find that your favorite pet seahorse greets you each morning with a special dance.

Keeping seahorses is not more difficult than keeping a reef aquarium, it’s just different. If you have reefkeeping experience, you will need to unlearn some of what you know and follow a set of seahorse specific rules.

Rule #1: Buy Captive Bred Only

Do not buy wild caught or net pen raised seahorses. Wild caught and net pen raised (maricultured) seahorses are initially less expensive than captive bred seahorses, but end up being more expensive in the long run. They most often carry pathogens that are expensive to treat and don’t always respond to the over the counter medications available to hobbyists.

Seahorse breeders sometimes purchase wild caught and net pen raised seahorses if the species isn’t available as captive bred. Experts recommend wild caught and net pen seahorses are always treated with a number of medications in a quarantine tank for a minimum of 9 weeks, but their survival rate is still fairly low. They usually won’t eat frozen foods and are already “walking dead” from starvation and handling stress when they arrive at your local fish store. Even if a seahorse is eating frozen food, if it is wild caught or net pen raised, chances are good that it’s carrying pathogens that will make it a ticking time bomb.

Beautiful wild-caught Brazliian H. reidi are tempting, but should be left to the seahorse experts.

Only buy captive bred seahorses raised by a breeder who uses a salt mix or properly sterilized sea water. There are a few reputable breeders here in the United States and Europe. You can order directly from the internet or ask your LFS to order them for you.

Ask other seahorse keepers in online forums or facebook groups which breeders they recommend. You can sometimes find captive bred seahorses at your local fish store. Ask the owner or fish buyer who bred the seahorses. If they don’t know, pass. If the breeder isn’t listed on their invoice, it’s probably net pen raised or wild caught. If they know who the breeder is, they’ll want to advertise that because captive bred seahorses are hardier and more valuable. Some net pen raised seahorses are sold as “tank raised” or “tank bred,” but the breeder isn’t known. In those cases, they’ve likely been raised in the same conditions as net pen raised seahorses and carry the same risks. Always find out who bred the seahorse before purchasing to ensure quality.

an exotic, spiky H. barbouri from SeahorseSource, a breeder in Florida

Captive bred seahorses, especially the US endemic Hippocampus erectus, are quite hardy. Contrary to popular belief, seahorses are not particularly fragile when they’re in good condition. They’re much more tolerant of handling than other fish because of their physical build. These demersal animals spend most of their lives with their tails and bodies wrapped around objects in their environments.

Just like puppies, seahorses should be a certain size and age before going to their new homes. It varies by species, but the common H. erectus should be 4 – 6 months old and at least 3” long before you add it to your aquarium. Seahorses smaller than this may not transition well to a new environment and require 4 or more feedings a day. Mature seahorses are hardier and only need 2 or 3 feedings a day. Most reputable breeders won’t sell their seahorses while they are small and still require many feedings a day.

If you’re buying seahorses from your local fish store or a local breeder, choose active seahorses with full bellies. Caved in sides are a clear indication of starvation and malnutrition or internal parasites. Ask to see the seahorses eat. They should be able to aim for the food accurately and not miss or struggle to suck food into the snout. Look for clear eyes and skin without lesions or swollen areas. It’s normal for seahorses to have a covering of fuzzy algae or Cyanobacteria growing on them.

Young seahorse fry covered in algae

Rule #2: Keep Your Tank Clean

Seahorses are not designed to eat dead food; in the wild they only eat live prey. Seahorses lack the gut associated lymphoid tissue in their digestive tract that helps protect most other fish from bacteria on decaying food. This is why it is very important to only offer very fresh frozen foods. If your frozen mysis is more than a few months old or looks brown instead of white, throw it out. Bacteria like Vibrio and Mycobacterium will quickly colonize decaying organic matter in the aquarium, and seahorses are particularly susceptible to these bacteria. If there is leftover food on the bottom of the tank, make sure to quickly siphon it out within an hour after feeding. It’s also wise to siphon out any feces before feeding to prevent accidental ingestion. You can use a simple hose and bucket or a siphon hose that hooks up to the sink. Use an algae scraper like a Mag Float to clean walls regularly. When you change your filter media, make sure you scrub inside your tubingpumps, filters as well.

Yellow H. erectus on a red sea star.

Rule #3: Maintain the Right Temperature

Seahorses do best in temperatures a bit lower than reef aquariums. Hippocampus erectus prefer temperatures between 68° F and 74° F. Other tropical species like H. reidi, H. comes, and H. kuda like slightly warmer temperatures between 72° F and 74° F. It is true that wild seahorses can be found at higher temperatures in the wild, but since tropical Vibrio bacteria thrive and become more virulent at temperatures above 74° F, captive seahorses do best at or below 74° F. If you’re keeping sub-tropical or temperate seahorses, ask the breeder or a seahorse expert what the correct temperature is for that species.

This seahorse hitched on a heater and was burned. Sadly, she died soon after despite treatment efforts. Photo credit DesertUSA

If you can not maintain a temperature of 74° F or below in your seahorse aquarium, you can use a fan to blow across the top of the water to bring the temperature down a few degrees. The water will evaporate quickly, so have plenty of fresh water on hand to top off the tank. If you need to bring the temperature down more than a few degrees, an aquarium chiller is recommended. You should choose a chiller that is slightly oversized, as this can increase its efficiency and lifespan. If your air conditioner breaks or your power goes out on a hot summer day, have plenty of frozen water bottles in your freezer that you can float in your seahorse aquarium to help keep the temperature cool.

Some seahorse aquariums won’t need a heater. If your home temperature in the winter is too cool or your home’s temperature unstable, you will need a heater. Never put a regular aquarium heater in the main display where seahorses have access to it. Unlike other fish that swim, seahorses will hitch on the heater. When the heater turns on, it will burn the seahorse which can lead to severe injury, infection, and death. You can keep your heater in a sump filter or the back filtration chamber of your all-in-one Innovative Marine or Red Sea tank, or use an in-line heater so your seahorses can not hitch to it.

H. erectus fry about to eat a live adult brine shrimp

Rule #4: Always Quarantine and Condition

It is strongly recommended to quarantine new seahorses, even if they are captive bred and you trust the breeder and supplier wholeheartedly. Seahorses are most often bred in large, sterile vats with one type of hitch and no sand or rock. When you bring home a new seahorse, chances are they’ve never experienced a typical aquarium environment, and it can take some time for them to get used to it. It’s not uncommon for even captive bred seahorses to stop eating frozen food when they’ve gone through shipping stress and then moved to a new environment. This is why quarantining them in a system that is similar to what they were raised in can increase your chances of keeping them alive. Seahorses are much more likely to eat frozen food in a bare bottom tank than a tank with sand. Condition and observe your new seahorses in the quarantine tank for at least 30 days before moving them to the display. Even if they’re your first seahorses, it’s a good idea to quarantine them so they can gain their strength before moving to the display. This will also allow you to observe them for any possible health issues or pathogens that you don’t want to infect the display tank with.

A simple, dimly lit bare bottom tank with a few hitches and a few pieces of cured live rock make a good quarantine tank. You can use cycled sponge filters or HOB filters. Feed at least twice daily and siphon uneaten food within an hour after feeding. Test the ammonia and pH daily and do water changes as needed.

If you have chosen to purchase wild caught or net pen raised seahorses, quarantine and conditioning is a necessity. The process is much longer, more complex, and involves a minimum 9 week de-worming treatment and frozen food training.

Australian pot-bellied seahorses require very chilly water to thrive.

Rule #5: Give Them Room to Grow

Most people only ever see young seahorses in person at pet shops. H. erectus and H. reidi can reach over 7” in length, some growing larger than an adult’s hand. You may be tempted to buy a smaller tank for young seahorses, but they grow so quickly you’ll need to upgrade to a larger tank within a few months.

erectus and H. reidi need a minimum of 30 gallons per pair, but do better with a 50 gallon or larger. Add 20 gallons for each additional pair. If you overcrowd your tank, you’ll find yourself struggling to maintain the water quality and prevent illness in your seahorses. This will end up costing more money and causing you and your seahorses undue stress.

Appropriately sized all-in-one tanks with open tops are perfect for seahorses. Enclosed all-in-one tanks like the Biocube and Nano Cube tend to run too hot for keeping seahorses. Innovative MarineRed Sea Max, and Red Sea Reefer style tanks are great options for seahorses. Seahorses prefer at least 24” of vertical height for their elaborate courtship and mating rituals.

It can be tempting for a lot of reefers to put seahorses in their existing aquarium’s sump away from their stinging corals and aggressive fish, but this is not a good idea. Reef temperatures tend to be too high for seahorses, and sumps, just like any filter, collect detritus that can attract bacteria and make your seahorses sick if they come in contact with it. Your skimmer pumps and return pump are a major risk for seahorses inside a sump; if they go through a divider or baffle, their tails can easily be caught and destroyed in these pumps.  Seahorses are messy eaters and will increase the nitrate and phosphate levels in your reef tank. Seahorses and other fish belong in the aquarium, not inside a filter.

If you would like to keep seahorses in an aquarium plumbed into your existing aquarium, keep in mind that the temperature will need to be lowered for the health of the seahorses. You will need to do more frequent water changes to control the nitrates and phosphates resulting from your seahorses’ feeding behavior. Hardy corals may do well in an aquarium shared with seahorses, but corals like SPS that prefer very low nitrates and phosphates and warmer temperatures may not thrive.

a herd of H. reidi enjoying a meal together in a large aquarium

Rule # 6: Proper Filtration and Flow Are Key

It is imperative to have enough flow and filtration in your seahorse aquarium. The advice to keep seahorses in a low flow aquarium is outdated. Years ago the majority of seahorses available were small, weak specimens that couldn’t handle normal flow, and this misconception that seahorses need low flow has persisted. The hardy, robust captive bred specimens available today thrive aquariums with normal flow rates. It’s perfectly acceptable to have ten or even 20 or more times turnover in your seahorse aquarium. What isn’t acceptable is a direct jet of flow or if the seahorses have nowhere to swim, dance, or escape heavy, turbulent flow. A spray bar or circle flow assembly can help you eliminate dead spots in the aquarium while giving your aquarium a gentle but high flow rate.

a beautiful pipefish and seahorse reef at the Shedd Aquarium with high flow

Avoid using powerheads or wavemakers in a seahorse aquarium. Seahorses will hitch to the powerhead grate and can get their tails stuck or severely injured by the impeller. If you have a powerhead, you must use a cover or net like a media bag that fits over the entire powerhead because a seahorse can even get into the front of a powerhead with strong flow. Covers on powerheads can be unsightly and will restrict the flow, but frequent cleanings can help.

The best type of filtration for a seahorse aquarium is a sump (the Red Sea Reefer all-in-ones come with simple to install sump filters). A sump can increase total system volume and has room for protein skimmersrefugiums, and media reactors. If your tank is not “reef ready” or drilled, you can add a hang on the back over flow box along with an aqualifter pump. Choose a sump and an properly sized return pump.

If you decide not to use a sump, choose the largest canister filter or HOB filter you can find. Seahorses require heavy filtration, so you’ll regret buying a filter that is merely adequate. With frequent feedings and waste, Seahorse tanks must have effective mechanical filtration—such as filter sockssponges or filter floss—to remove particulates from your aquarium water. These mechanical filters need to be cleaned or replaced often to avoid a build-up of nitrates.

skimmer is a highly recommended piece of equipment for a seahorse tank. It was once believed that rogue skimmer bubbles were responsible for Gas bubble disease and pouch emphysema, but today we know that isn’t true. Skimmers actually prevent these ailments by driving off supersaturated gases and removing organics. (prevent GBD by keeping nitrates and organics low and always match the temperature of your water change water.)

UV sterilizers are another must-have piece of equipment. They won’t entirely eliminate pathogens like VibrioMycobacteriaUronema, and ciliates, but along with proper tank maintenance, they can reduce these pathogens to levels that are easily handled by the seahorse immune system.

Reactors can be useful in seahorse aquariums that have chronically high nitrate or phosphate levels. NP style bio-pellets in bio-pellet reactors are recommended for seahorses.

Check out our handy Reef Tank Packages section which will help you choose all the right equipment for your size tank.

Rule #7: Watch Your Water Parameters

Seahorses are sensitive to low pH and high ammonia. Low pH can cause them to lose their appetites, and high ammonia can burn their sensitive gills and eyes and kill them rather quickly. They’re tolerant of nitrates, but it is still good practice to keep nitrates below 20 ppm because high organics can cause infectious bacteria to bloom. Seahorses need calcium to maintain their bony plates, so keep your calcium and alkalinity levels stable. Salinity should be stable and measured with a refractometer. Specific gravity can be kept between 1.020 and 1.025.

Young H. kuda on a gorgonia skeleton

Rule #8: Create a Seahorse-Friendly Aquascape

Dry Live Rock is perfect for seahorse tanks because it does not contain pests like Aiptasia anemones which can sting and irritate seahorses. Use a variety of shapes including branching live rock for seahorses to hitch on. Live fancy macroalgae can give your seahorses holdfasts as well as control nitrate levels. You may incorporate artificial decor into your aquascape, but make sure the materials are saltwater safe. Not all aquarium decorations are safe for use in saltwater.

This gorgeous male Bluestripe Pipefish is a challenge for reefkeepers and seahorse experts

Rule #9: Keep New Seahorses in a Species-Specific Tank

It is best to keep young, small or new adult seahorses in species-only tanks until they are mature and conditioned. Turn down the light intensity and flow in the display tank a bit while they are adjusting to their new environment. Once your seahorses have gone through quarantine and conditioning, are eating well and fully mature, and have adjusted to the display tank, you may add safe tank mates to the aquarium.

Hardy, photosynthetic Gorgonians make wonderful tankmates for seahorses

Rule #10: Be Mindful About Coral Compatibility

Seahorses are compatible with most soft corals like ZoanthusXenia, Cabbage leathers, Tree corals, Spaghetti Finger Leathers, Gorgonians, and small mushrooms. Compatible LPS are not able to consume a seahorse and do not sting. These include TubastreaScolymiaAcanthastreaLobophylliaTurbinaria, etc. Do not house seahorses with any species of coral that could consume the seahorse like Elephant ear mushrooms or LPS corals with large mouths. Stinging corals are extremely dangerous for seahorses. Never put anemones, EuphylliaGalaxea, or other stinging corals with your seahorses. It is difficult to keep SPS corals with seahorses. Seahorse aquariums tend to have higher nitrate and phosphate levels than SPS corals prefer, and seahorses tend to irritate the SPS by hitching on them.

Euphyllia spp. like frogspawn, torch, and hammer corals are never safe tank mates for seahorses

Rule #11: Don’t Forget About Fish Compatibility

Most fish are not good seahorse tank mates. Some obvious no-nos are triggerfish, puffers, large angels, sharks, aggressive wrasses, Eels, stinging fish like Lionfish, etc. Some seemingly peaceful fish like blennies and clownfish are also risky. Seahorses are not able to escape or defend themselves against attacks even from small fish. Young clownfish can be suitable tank mates, but once they reach maturity, their aggressive behavior poses a serious threat to seahorses. Always have a backup plan when you’re adding fish to a seahorse aquarium. Some fish can be model tank mates for months or years before viciously attacking a seahorse. Make sure you’re able to remove the offending fish if it becomes a problem. Don’t take unnecessary risks, as they usually end in disaster. Remember that your seahorses are more susceptible to some pathogens than other fish, so quarantine all new fish before introducing them to your seahorses to prevent disease outbreaks.

Fish that are always compatible with conditioned seahorses include tiny gobies like Clown, TrimmaEviota, and Stonogobiops; Dragonets and Scooters; and small, peaceful gobies like Curious Wormfish and Eel Gobies.

War Paint Gobies are tiny, adorable, and peaceful additions to any seahorse tank

Fish that are usually compatible with large adult seahorses include Royal Gramma Basslets, very small Anthias species, Ecsenius Blennies, small Cardinalfish, Dartfish and Firefish, larger Watchman Gobies, small Jawfish, Flasher Wrasses, Assessors, and small Hoplolatilus Tilefish.

D. pessuliferus, the Yellow Banded Pipefish

Pipefish and related species like Sea Moths are compatible with seahorses in terms of temperament, but remember that these are wild caught relatives of seahorses and can easily transmit pathogens to your captive bred seahorses. Many seahorse keepers opt to keep wild caught pipefish separate from their seahorses. If you choose to take the risk, make certain you are quarantining and de-worming your new pipefish for a minimum of 9 weeks before introducing them to your seahorses. This procedure is well documented online. Also remember that wild caught pipefish are difficult to keep in captivity.

Dragonface Pipefish are one of the few Syngnathids that do well in SPS tanks. They’re often used to control Acropora pest red bugs.

Rule #12: Invert Compatibility Matters, Too!

Most small snails are great tank mates for any seahorse. Nassarius snails will help keep the tank clean by eating leftover food you may have missed while siphoning. Tiny hermit crabs are generally safe, but avoid larger crabs that can pinch and injure your seahorse. Clams and scallops can injure or trap a seahorse. Some sea stars and urchins are predatory, so use caution. Small shrimps like Sexy shrimp will be a snack for most seahorses, but medium shrimp like Peppermint shrimp are good tank mates. Avoid cleaner shrimp that may harass and stress seahorses. Large shrimp or lobsters pose a threat to seahorses. Porcelain crabs and small ornamental squat lobsters are peaceful and compatible with seahorses. Feather dusters and non-toxic filter feeding cucumbers are also safe.

Seahorses learn to recognize their humans and will readily eat Mysis shrimp from your hand

Rule #13: Feed Seahorses a Varied Diet

Mysis shrimp is the best staple diet for seahorses. Spirulina enriched frozen brine shrimp contain high amounts of vitamin E and are recommended as treats a few times a week to prevent vitamin E deficiency and myopathy, but don’t have enough highly unsaturated fatty acids to be the main diet. Copepods are excellent nutritious sources of HUFA, but some adult seahorses may not notice them because of their small size. Experiment with different frozen foods to find out what your seahorses like so you can offer them a varied diet.

Rule #14: Vitamins Can Help Prevent Nutritional Deficiencies

Brightwell Aquatics AminOmega is a great HUFA supplement. It is so concentrated, it can even be used to raise seahorse fry. You can use this product to gutload live adult Artemia, or you can soak frozen food in it. Also adding vitamins to your frozen food will help prevent nutritional deficiencies.

Many seahorse keepers train their seahorses to eat from a feeding dish or large seashell. You can also use a product like the CPR Smart Feeder to target feed slow or picky seahorses. It allows you to place the food close to the seahorse instead of broadcasting it all over the tank to be picked up by the filtration or lost under rocks.

This seahorse appears to be thin and unhealthy. Note the deep indents between trunk rings.

Rule #15: Conservation Status – Don’t Believe The Hype

It is a common misconception that seahorses are endangered. Only one species of seahorse, Hippocampus capensis, the African cape seahorse, is endangered in its natural habitat because of pollution, habitat loss, and freshwater run-off. It is not common in the aquarium trade and no longer available for sale in the United States because of low demand. H. capensis is relatively easy to breed in captivity, but prefers cool water and requires a chiller. A few other species of seahorses live in very deep or remote places, so scientists are unable to assess the health of their population.

Today the aquarium trade has very little impact on numbers of wild seahorses. Most seahorses purchased for pets are now bred in captivity. All seahorses are protected by CITES because populations were in decline due to use in the Traditional Chinese Medicine Trade and the Curio souvenir trade.

Seahorse with a small lesion. Address injuries and infections immediately.

Rule #16: Stock Your Medicine Cabinet

Seahorse keepers are urged to have a “medicine cabinet” for their pets. When seahorses get sick, it happens quickly. Some infections can kill in 24 hours. You probably won’t have time to wait until after work to pick up medicine locally, and waiting a day or two for them to arrive in the mail is very risky. Having these medications on hand at all times will allow you to treat your sick seahorse right away and greatly increase their odds of survival. Make sure to replace them when they pass the expiration date!

Before using these medications on your seahorses, please consult a seahorse expert at Marine Depot, a seahorse group on Facebook, or a seahorse forum. These medications must be used in a quarantine or hospital tank unless otherwise directed. Always wear gloves when handling meds and changing water in your hospital tank.

Recommended Medications:


  • API Furan 2
  • Seachem Kanaplex (kanamycin)
  • Neosporin (yes, the human kind. Make sure it has no added ingredients)

Anti parasitic


Unsafe medications for Syngnathids

  • Copper
  • MelaFix