A Felicia's Aquarium Adventures reader, Jim Bremner of www.desertusa.com (very cool website, worth a look), was kind enough to share the story and photos of his seahorse that was badly burned by an aquarium heater. Jim is an avid aquarium keeper, but is fairly new to seahorses. In all his extensive research, he never found advice about not keeping a heater in a seahorse tank. Truly, this small but very important piece of advice is often left out of seahorse care articles.
Aquarium heaters can and do burn seahorses, and it is a life-threatening situation. Most seahorse aquariums do not require aquarium heaters, as seahorses do best in temperatures lower than 74°F. If you need a heater in your seahorse tank to raise or stabilize the temperature, use an inline heater, a heater guard, or place the heater in a sump.
This is what a heater burn looks like. Notice that the skin has been burned away but is not swollen or infected. With any kind of burn or injury, Vibrio bacterial infection can set in very quickly and aggressively, so it's best to get the seahorse moved to a hospital tank with a controlled temperature no warmer than 68°F. Have the proper antibiotics on hand (Triple Sulfa or Furan-2 combined with Neomycin) and keep a close eye on the burn for sings of infection. If the white area gets larger or changes in appearance, start treating with anti-biotics. Use the full course of antibiotics, even if the seahorse appears to be fully healed. Give the seahorse soft airline tubes to hitch on (if he will hitch), keep the lights dimmed, and avoid sudden movements around the tank. If the seahorse stops eating, offer live mysis or enriched live adult brine shrimp.
Jim did everything he could to save his seahorse, but unfortunately, the seahorse did not survive. Thanks again to Jim for sharing his photo and story with us. Maybe his experience will help save the lives of other seahorses.