Mar 29, 2009

Longfin Fairy Wrasse and Yellowfin Flasher Wrasse

I promised to update with better photos of my longfin fairy wrasse in previous blog entry. I also wanted to show off my male yellowfin flasher wrasse Paracheilinus flavianalis named Mercury. I've had him for a few weeks now, and he is doing great. They eat frozen mysis and cyclops, but also eat live amphipods they catch in the aquarium. The two wrasses get along famously and follow one another around, pecking at the live rock. Mercury regularly flashes and flares for her, and I think she looks impressed. They must not care that they belong to different genera!Paracheilinus flavianalis

Cirrhilabrus rubriventralis

Sea Cucumber Feeding and Parasitic Snail

I bought a beautiful pink and yellow sea cucumber Pentaca anceps on Thursday from my local shop. Unlike their substrate-crawling cousins, these sea cucumbers are filter feeders like the very closely related sea apples. I'm aware that they can be poisonous when they are stressed or die, but I've read that this species is less likely to "go nuclear" than the larger sea apples. Just in case, I have stocked up on fresh carbon, polyfilters, and some extra water-change water.

I was half expecting to find some hitchhikers on the sea cucumber; they are pretty common. Crabs, fish, and snails are known to live in or on sea cucumbers. Some are parasitic, feeding on the internal organs or skin of the cucumber, and others, like the pearlfish and swimmer crabs, are commensal.

Here you can see the snail on the cucumber. The snail is hard to see because it is the same color as the cucumber and looks like just another a knobby part on the sea cucumber. The snail in this photo is located just below the feather feeding tentacles. Click on the photo for a larger view.

When I finally noticed this snail, which is roughly the size of a grain of rice or slightly smaller, I pulled it off with some tweezers. Its shell was very slippery and hard to grasp, even with the metal tweezers. When I started to grasp it, it seemed to hold to the sea cucumber tighter.

Don the snail expert from was kind enough to try to ID this parasitic pyramid snail for me. He believes it may be a Melanella araeosomae of the family Eulimidae. He doesn't think it's something to be overly concerned about, as the snails do little damage to their hosts. He also told me that the shells of these snails are clear, and that the color we are seeing is the color of the actual body of the snail inside the shell.

Baby brine shrimp and Rotifers are too large for sea apples and sea cucumbers to digest. Because the tentacles are so sticky, aquarists have witnessed what appeared to be the sea apple or sea cucumber eating brine shrimp, when in fact it was simply stripping the unwanted "debris" from the tentacles and discarding it. In the home aquarium sea apples and sea cucumbers must be fed phytoplankton several times a day to remain healthy.

  "Studies in which researchers sifted the gut contents of a variety of suspension-feeding sea cucumbers found that all but one species ate only particles of less than 53 μm in diameter (for comparison, newly hatched brine shrimp are approximately 400 μm, and my survey of commercially prepared invertebrate foods found such products contained a mean particle size of 365 μm 696 μm, see Toonen et al. 2002). Researchers have found that the majority of the diet of suspension feeding sea cucumbers such as sea apples consist of phytoplankton cells (primarily larger species of phytoplankton such as Coscinodiscus, Chaetoceros, Skeletonema, and Thalassiosira), with occasional ingestion of tiny invertebrate eggs and larvae (Hamel & Mercier 1998). In fact, even full-grown rotifers (which average between 75 and 300 μm, depending on the strain) are too large for most suspension feeding cucumbers to eat..."

Read the full, informative article by  Rob Toonen, Ph.D for Advanced Aquarist's Online Magazine.

Mar 25, 2009

New Erectus Seahorse Pictures

Some pictures of some of my adorable juvenile Hippocampus erectus seahorses. These are large seahorse wallpaper photos; click on the photo and view the "original" image to get the largest size. The white seahorse at the top and the black seahorse at the bottom are the same individual. Her name is "Kuiter;" she changes color often.

White Seahorse

Seahorse with cirri

Hippocampus erectus

Hippocampus erectus

Hippocampus erectus

Hippocampus erectus

Seahorse friends

Mar 21, 2009

Seahorse Courtship Video

I shot a couple of short videos this week of my seahorses. The fist video is of Juniper and Ellis courting. Both are normally black, but Ellis turns reddish pink and Juniper turns silver. You can see the color change pretty well in the video. Juniper tries to impress Ellis by doing a lot of pouch flushes and crunches.

Sorry the glass has so much salt on it. I didn't want to disturb them. I didn't get the actual egg transfer; I'm not even sure if they know how to do that yet.

This second one is a video of my seahorses wrestling, holding tails, and just hanging out and being friends.

Mar 18, 2009

Purple Zebra Porcelain Crab

I snagged an interesting Nano crab from Liveaquaria today. Sign yourself up for the RSS feed to keep up with all the cool species posted there. I've never seen one of these guys before! It's really similar to the Petrolisthes galathinus from the Caribbean. This species Petrolisthes bolivarensis was once thought to be a variation of the P. galathinus, but was given its own species name in 2002.

Petrolisthes bolivarensis

It has a few unique markings to help identify it. There are two small orange dots on each claw and a zebra pattern of distinct purple lines on the body. It has vivid blue mouthparts and a purple underside.

Like other Porcellanid crabs, this crab is totally reef safe and peaceful. It is not commensal with anemones like Neopetrolisthes sp. porcelain anemone crabs. It uses two feathery baskets at the end of its feeding arms (third maxillipeds) to filter food from the water column. It will also accept bits of mysis and other foods when target fed.

Further Reading:

Mar 12, 2009

Seahorse changing color

Here is a short video of my seahorse changing color from black to silver. The clips were taken over about 2 minutes. She is normally black or black with silver saddles. She can change color spontaneously and likes to turn pure silver when she is eating or dancing.

Mar 11, 2009

New seahorse video

My seahorse aquarium with 3 juvenile seahorses, 2 adult seahorses, bluestriped pipefish, Trimma goby, red scooter dragonet, and squat lobster. The Brotulids are hiding, sorry.

Mar 6, 2009

Ancient Ancestor of our Aquarium Crabs?

This fossil crab is a Galena bispinosa from the Pliocene epoch. It is estimated to be 2 million years old and was found on the west side of the Cape York Penninsula, Queensland, Australia. Click on any photo for a much more detailed view.

These crab fossils are pretty inexpensive if you can find one. I bought this one a couple years ago for my husband, who wanted to be a paleontologist when he was little. I was really lucky to find one (the fossil) in such good shape.

The pair of crabs pictured here are in the Humbolt State University National History Museum. It amazes me how much these fossil crabs looks like crabs that are alive today.

When I first saw this fossil, I thought of how much it reminded me of modern shameface crabs and strawberry crabs. The photo on the left is a Liomera bella, a type of strawberry crab. This photo was taken by Bryan Harry.

The red crab in the photo on the left is a type of Xanthid crab that lives in isolation in my aquarium. I punched holes in a plastic water bottle and attached the airline hose from my Aqua Lifter pump for water circulation. Xanthid crabs are known for being destructive in aquariums. This particular crab was found as a hitchhiker on some live rock (I took out the piece it was on and gave it a hyper-salinity dip. Crab came right out). It was too pretty for me to "get rid of," so I kept it! It's very hardy and eats algae and frozen mysis.

Below are some different views of our crab fossil. We have a few more neat marine-life fossils, so look for more fossil-related posts in the future.

Sexy Shrimp - Perfect Nano Shrimp

A very popular Nano aquarium crustacean is the sexy shrimp, Thor amboinensis. These shrimp hold their abdomens straight up and wave them back and forth, which is how they got their name. These diminutive shrimp only grow to a little over an inch in length. In the wild they live among the tentacles of anemones, but will live on Ricordea or other mushroom corals in the aquarium. They are very peaceful shrimp and may be kept in groups. In the wild they eat the mucous from their host anemone and any food that gets stuck to the tentacles. In an aquarium, they will eat meaty foods like frozen mysis, cyclops, or brine shrimp.

Mar 4, 2009

Acropora Crabs Commensal Guard Crabs

Trapezia cymodoce in Acropora secale

Keeping Acropora corals and other SPS alive in captivity can be a challenge, But you can enlist the help of tiny Commensal Acropora crabs and Pocillopora crabs of the Trapezia and Tetralia genus. These crabs are extremely beneficial to Acropora and other SPS corals. They protect the corals from some predators and keep the coral clean. If your aquarium houses SPS (small polyp stony) corals like Pocillopora or Acropora corals, these crabs should acclimate well and be easy to keep. These tiny crabs are very territorial, so only one should be kept per coral unless they are a mated pair. These tiny crabs can be found as hitchhikers on SPS corals or can be purchased online.

Trapezia septata lives in Pocillopora
Trapezia crabs can measure up to 1-3/4″ from elbow to elbow. They are also “equal handed,” having same-sized chelipeds (claws). Trapezia crabs are symbionts on Pocilloporid corals. Trapezia cymodoce, Trapezia septata, and the beautiful, red-spotted Trapezia rufopunctata host on Pocillopora corals, while the brown-clawed white Trapezia guttatus hosts on Seriatopora Birdsnest corals. These crabs are perfectly camouflaged to their host coral. The legs of T. guttatus are almost identical to the branches of a Birdsnest coral, and the spots of the T. rufopunctata mimic the host coral’s polyps and color.

Trapezia guttata lives on Seriatopora
The Birdsnset Coral Crab, Trapezia guttata, lives in Birdsnest corals of the genus Seriatopora. They may live on other species of SPS if no Birdsnest corals are present. Notice the legs of the crab are nearly identical in markings, texture, and shape to the branches of a Seriatopora hystrix. Even false polyps are present as dark markings on the brown legs.

Tetralia spp. live on Acropora
The tiny Acropora Crabs of the genus Tetralia rarely measure more than 3/4″ and have one claw that is larger than the other. It’s not uncommon to see these crabs living in corals as pairs. Tetralia Crabs are commonly found as hitchhikers on wild Acropora colonies, and only host on Acropora corals. These crabs come in a wide array of colors. They are usually purple, white, or orange and have a brown, black, or blue “mask” across the eyes, giving them the common name “bandit crabs.”

In captivity it’s best to keep large Trapezia crabs on larger SPS colonies. Their activities have (uncommonly) been reported to cause damage to smaller colonies or frags. Guard Crabs are beneficial to their host corals, as they protect the coral from some pests, predators, and settling sediment. In the wild scuba divers see them pinching the underside of the crown of thorns star – a large predatory sea star that consumes coral – until it moves on to an unprotected coral. I’ve personally witnessed an Acropora crab evict a smaller pest blue eyed crab from its host coral. Blue eyed crabs can cause serious damage to the coral colonies they inhabit. Guard Crabs also remove debris that settles on the host coral, preventing tissue necrosis. In turn the crab gets a home and a free meal.

"The scientists showed the importance of trapeziid crabs by gently removing crabs from sections of the two species of branching corals on a coastal reef. This resulted in 50 to 80 percent of those corals dying in less than a month. By contrast, all corals with crabs survived...For surviving corals that lacked crabs, growth was slower, tissue bleaching was greater, and sediment load was higher. Laboratory experiments revealed that corals with crabs not only shed substantially more of the sediments deposited on coral surfaces, but also that crabs were most effective at removing grain sizes that were most damaging to coral tissues." - from Tiny Crabs Project

Pocillopora and Acropora Guard crab food is provided entirely their host coral. They are easy to keep in captivity, but must be given an SPS coral to host on.

See more photos and read more about Commensal coral crabs at

Mar 3, 2009

Pom Pom Crabs - Perfect Nano Crabs

Since Nano aquariums have become popular, hobbyists are always looking for tiny, peaceful animals to live in them. I think crustaceans make excellent Nano tank inhabitants because they produce less waste than fish and need less room.

One deserving Nano crustacean is too often overlooked because it is cryptic and nocturnal - the pom pom crab, Lybia tesselata. See one of my pom pom crabs pictured below.

pom pom crab

Probably the most fascinating aspect of these crabs is their symbiotic relationship with tiny anemones of the genus Triactis or Bunodeopsis. The crab holds the anemones (which contain stinging nematocysts) in each claw and uses them for defense. These crabs literally pack a powerful punch. I once saw one of my gobies try to evict my pom pom crab from its hole in the rock when the crab "punched" the goby in the face with its anemone. There was no permanent harm, but I'm sure the goby will think twice before trying that again. Pom pom crabs also use their anemones' sticky tentacles to help them "mop up" food. This feeds the crab, and in turn, feeds the anemones. The crabs mostly eat meaty foods and are considered aquarium scavengers. They should be target fed in the aquarium.

Pom pom crabs are naturally nocturnal and very cryptic. When housed in a large or medium sized aquarium, they will rarely be seen. The best time to view them is at night, with the lunar lights on. The crabs are very hardy and can be housed in a small aquarium with no problem. However, the anemones can not tolerate unstable water parameters and often die shortly after being added to an aquarium. Nano aquariums are known for having unstable salinity and water parameters. This is why it is best to add your pom pom crab only to a well established, stable Nano aquarium. An auto top off system can help with this.

pom pom crab with eggs

If your pom pom crab loses one of its anemones, it can split the other in half and make two anemones. If your pom pom crab loses both anemones, it will still survive, but may start chopping up and carrying around your Zoanthus or coral polyps. If you have more than one pom pom crab, these social creatures will actually share anemones. If a crab loses both anemones, its generous "friends" may cut one of theirs to give.

Some people consider these crabs not to be reef safe because of the stinging power of its anemones. I believe that since the anemones are so tiny, they pose no threat whatsoever to healthy corals or fish. I even keep mine with seahorses and tiny gobies.