I’m very sorry to hear about the problems you have been having with your female seahorse, Jenn. It sounds like you did a wonderful job of nursing your pony through a case of gas bubble disease, and you certainly addressed that problem correctly. Well done.
The behaviors you described bring a a few different things to mind. I don’t have a really clear idea of what is going on with your pony at this point, but I would be happy to share my thoughts on the matter with you.
For instance, you mentioned that your female had stopped eating and needed to be hand fed, and that it was crashing into things when returned to the main tank following treatment in your hospital tank. Those are things that suggest you could be dealing with temporary blindness.
Over the years I have encountered several instances of blindness in seahorses, Jenn. Two of them were the result of severe bilateral exophthalmia (commonly known as Popeye), which caused functional blindness and prevented the seahorses from feeding properly. In a few other cases, the apparent blindness was associated with high intensity lighting, so if your quarantine tank is brightly lit, the seahorse’s eyesight may have been impaired as a result.
In short, I know of a few seahorses that have developed blindness and it’s not as uncommon as you might expect. Some of the marine fish that are especially prone to this problem in captivity are lionfish, large angelfish of various species, seahorses, clownfish, and large puffers and porcupine fish.
In most of the cases I am familiar with, the blindness was caused by exposure to bright lighting under circumstances when there was no way available for the fish being displayed to seek shelter and get out of the light when they wanted. When that’s the case, the blindness is often temporary, and the affected fish’s vision can be restored by maintaining it in total darkness for an extended period of time. Apparently the complete absence of light is beneficial or therapeutic in some cases of blindness, and the affected fish are normally hand fed well they are recovering…
For example, this is what Robert PL Straughan (Saltwater Aquarium in the Home) reports regarding blindness in aquarium fishes, Jenn:
“When a fish suddenly shows no interest in food, it may have gone blind. Excess light is usually the cause, especially when the fish is not given a dark hiding place in the aquarium where it can go once in a while. The fish may bump into coral or snap at food which it can feel or sense but cannot see, and prompt action must be taken to save your pet. You can usually see if the fish is blind by moving your hand quickly in front of the glass. If he shows no response even though you attempt to frighten him from the outside, and if he swims to the end of the aquarium and bumps into the glass or coral, then he is most likely blind. This does not necessarily have to be a permanent condition and it can usually be cured, with time and patience.
“First remove the victim to a separate aquarium, and cover the sides and top of the tank with cardboard to keep out most of the light. Since the fish is blind, it will have to be hand fed and this may be accomplished by holding the fish gently with one hand and forcing chunks of chopped shrimp into its mouth with the other. Usually, if the fish is tame, it will accept food eagerly in this fashion and if it does, it is well on the road to recovery. Usually when hand feeding a blind fish, it is best to handle the fish very gently so that it will not become excited, then release it equally as gently after the food has been placed well in its mouth. It will usually swallow the food and the whole procedure may be repeated until the fish has eaten his fill.
“If, after a week or so, the fish responds to light, remove one side of the cardboard so that the aquarium will be partly lighted. The fish may be returned to the regular aquarium after its sight has returned, but this time, it should given a good coral hiding place so that it can get completely out the light when it desires. This is a perfectly natural situation as anyone who has observed marine life on the reef can testify. The fish will swim out into the bright sunlight for brief periods of time and then periodically retreat to the dark seclusion of a coral ledge or other protection.
“Large Porcupine fish, Rock Beauties, and Angelfish, are especially susceptible to blindness from too much light, and can be blinded in a matter of hours if left in direct sunlight with no cover or protection. Also the Lionfish, Clownfish, Seahorse and any other fish which tend to stay out in the open, can be blinded if subjected to intense aquarium light.” This condition is often brought on, when fish are placed on public display. The lights are left on for long periods of time, and the fish are given no place to hide so that usually in a week or so, the fish are blinded.”
Robert P.L. Straughan, The Salt-Water Aquarium in the Home, A.S. Barnes & Company, 123-124.
So marine fish can be blinded by intense light if they have no opportunity to escape from the bright lighting for an extended period, and our prize ponies are among the fish that are most susceptible to this problem, Jenn. Seahorses with impaired vision stop feeding (they are of course visual hunters) and typically stop moving around since they cannot see where they are going to avoid obstacles.
However, from what I have gathered, the blind seahorses I know of all readily accepted handfeeding and seemed to realize that the hobbyist was trying to help them by offering food in this manner.
So if you have recently changed your aquarium lighting, especially if you have upgraded to high-intensity lighting such as metal halides for the sake of live corals or some such thing, it is possible that your female may have gone blind, Jenn. On the other hand, fish will blindly crash into objects and bang into the sides of the aquarium in a panic when they are frightened or startled, so your female seahorse may be able to see perfectly well. There is no way for me to determine that from afar…
Another possibility is that your female seahorse has an underinflated swimbladder and is suffering from negative buoyancy (the tendency to sink) as a result. Fish with an underinflated swim bladders always tend to stay at the bottom of the aquarium because it requires great effort for them to swim upwards. An underinflated gas bladder can happen as a result of stress and pH shifts during acclimation. Fortunately, that’s a problem that a seahorse can correct itself, using the gas gland in the lumen of its swim bladder to slowly add more oxygen to the swim bladder. This may take several days as the seahorse’s blood chemistry returns to normal and it gradually reinflates its swim bladder.
When seahorses are swimming and want to ascend, they will lift their heads and extend their tail out straight beneath them and hold it extended in order to shift their center of gravity and make it easier for them to rise. Likewise, when a swimming seahorse wishes to descend in the water column, it will tuck its head and curl its tail beneath it in order to shift its center of balance and make it easier to swim downward. The contorted body movements you describe and the unusual way your female is holding its tail could be an indication that it is struggling to swim normally due to an underinflated swimbladder, Jenn. If so, that’s merely a temporary problem that the seahorse should be able to resolve on its own.
On the other hand, if a seahorse that is holding its tail behind its body forming a “U” shape, that could be an indication that its tail is very tender and sensitive, and is often an early sign of tail rot or white tail disease, Jenn.
Such diseases begin with a loss of prehensility in the very tip of the tail (Giwojna, Oct. 2003). At this stage, the seahorses can grasp large objects just fine, but cannot take hold of slender objects with a small diameter (Leslie Leddo, pers. com.). Next the loss of prehensility spreads further up the tail and the seahorses begin to act as if their tails are very tender and sensitive. They will drape their tails over objects rather than grasping onto them and begin to drag their tails behind themselves, often arching the end of their tail upward in the shape of “U” (rather than the usual “J” or tight coil) as if to lift it off the ground and keep it from touching anything (Leddo, pers. com.).
This is usually when the tip of the tail becomes white and the loss of coloration starts advancing further and further up the tail (Giwojna, Oct. 2003). At this point, the discolored skin begins to flake or lift up and open wounds and ulcers develop on the most distal portions of the tail (Giwojna, Oct. 2003). The infection attacks the underlying tissues, and the tail is gradually eaten away, often all the way to the bone, exposing the vertebrae (hence the name Tail Rot). Survivors may end up missing the last few segments of their tail (Giwojna, Oct. 2003).
In short, you need to keep a close eye on your female at this point to make sure that it is not developing tail rot, Jenn. Many times tail rot is associated with heat stress, but your water temperature is excellent, which would seem to eliminate heat stress is a factor in this case. It would also be unlikely for a seahorse to develop tail rot after being treated with antibiotic therapy in your hospital tank, so I just can’t be sure of any sort of a diagnosis or prognosis with so little to go…
If you contact me off list at the following email address ([email protected]), I can provide you with additional information, Jenn. Please keep me updated on the progress of your female seahorse. Hopefully, she will soon settle down, begin eating and swimming normally again, and and be none the worse for wear following the episode of gas bubble disease.
Pete Giwojna, Ocean Rider Tech Support