Dear Mardean:
I’m very sorry to hear that you lost the female after all. All my condolences on your loss, Mardean!
Clearly something more was bothering her then the irritation from algae growing on her, but it’s very difficult to determine what was wrong with so little to go on. Sunbursts are a bit smaller than Mustangs on average, but I would not have expected your female to be half the size of the others, and if she was simply a younger seahorse, then one would expect to see a faster growth rate from her as compared to the more mature seahorses. But that’s not what you observed, which does suggest that something may have been bothering her for quite some time now.
Intestinal flagellates may be one possibility, Mardean. When a seahorse is a good eater yet fails to grow as expected or loses condition despite a good appetite, that can be an indication of a heavy infestation with intestinal flagellates, as discussed below:
Intestinal Flagellates
Intestinal flagellates are microscopic organisms that move by propelling themselves with long tail-like flagella (Kaptur, 2004). Such flagellates are ubiquitous and can be found in both the gastrointestinal and reproductive tracts of their hosts. In low numbers they do not present a problem, but they multiply by binary fission, an efficient means of mass infestation when conditions favor them (such as when a seahorse has been weakened by chronic stress), Kaptur, 2004. When they get out of control, these parasites interfere with the seahorse’s normal digestive processes such as vitamin absorption, and it has difficulty obtaining adequate nourishment even though it may be eating well and feeding heavily (Kaptur, 2004). Suspect intestinal parasites are a work when a good eater gradually wastes away despite its hearty appetite (Giwojna, Dec. 2003). Their presence can be confirmed by examining a fecal sample under a microscope, but they can be easily diagnosed according to the more readily observed signs described below (Kaptur, 2004).
The symptoms to look for are a seahorse that’s losing weight or not holding its own weightwise even though it feeds well, or alternatively, a lack of appetite accompanied by white stringy feces (Kaptur, 2004). When a seahorse stops eating aggressively and begins producing white, stringy feces instead of fecal pellets, that’s a clear indication that it’s suffering from intestinal flagellates (Kaptur, 2004). Treat the affected seahorse(s) with metronidazole at the first sign of either condition (Giwojna, Dec. 2003).
Metronidazole is an antibiotic with antiprotozoal properties that is very effective in eradicating internal parasites in general and intestinal flagellates in particular (Kaptur, 2004). It is ideal for this because it is rapidly absorbed from the GI tract, has anti-inflammatory effects in the bowel, and was designed specifically to treat protozoal infections and anaerobic bacterial infections by disrupting their DNA (Kaptur, 2004).
When administered properly, metronidazole is wonderfully effective at eliminating intestinal parasites, and there should be signs of improvement within 3 days of treatment (Kaptur, 2004). The seahorse’s appetite should pick up, and as it does, those characteristic white stringy feces will return to normal (Giwojna, Dec. 2003).
Intestinal parasites are typically transferred from their host to uninfected fishes by fecal exposure, and good tank management and hygiene can therefore go a long way towards limiting their spread (Giwojna, Dec. 2003). You don’t want seahorses eating frozen Mysis that may have become contaminated from laying on a dirty substrate (Giwojna, Dec. 2003). Using a feeding station can help prevent this as can vacuuming the substrate regularly.
Fortunately, intestinal flagellates have virtually no ability to survive outside their host’s body (Giwojna, Dec. 2003). If you are diligent about aquarium maintenance and keeping the substrate clean, Mardean, the parasites should be easily eliminated from your system and chances are good the rest of your herd will remain unaffected (Giwojna, Dec. 2003).
It’s difficult to determine if your Emerald Mithrax played a role in the female’s demise or if the crab was simply scavenging the carcass of the seahorse after it had died. Emerald Mithrax crabs are primarily herbivorous in nature and are generally shy and inoffensive in the aquarium. I would say that 9 times out of 10, Emerald Mithrax make fine tankmates for seahorses and cause no problems at all. It’s just those rare exceptions and uncommonly cantankerous individuals you must be wary of, Mardean. Even the gentle Emerald crabs can very occasionally become problematic if they are not getting enough vegetable matter in their diet, in which case they may become opportunistic omnivores and are no longer averse to adding a little meat to their diet should they get hungry enough.
Remember, crabs and crustaceans in general are opportunistic predators that are liable to attack anything they can overpower. They may be entirely peaceful and inoffensive when they are small, but even a small crab can cause a lot of trouble as it grows. They may double in size following a molt (i.e., ecdysis) so they grow surprisingly fast, and even a tiny crab that’s completely docile at first can grow large enough to turn predatory almost literally overnight if it’s a species that reaches a respectable size. One day it’s a miniature crab that’s cute and entertaining in its own bumbling sort of way, and the next day following a successful molt, it can become a dangerous bully that regards its tankmates with a culinary eye.
Keep in mind that there are always exceptions to every rule, and large crustaceans are never completely trustworthy. Even the most harmless and seemingly inoffensive crabs can cause trouble under certain circumstances. For example, not long ago I heard from a hobbyist that had been keeping a decorator crab in his seahorse tank. All went well at first and there were no problems of any kind for months until, for no apparent reason, the crab suddenly began to quite deliberately amputate portions of the seahorses’ tails. It was not attacking the seahorses as prey or attempting to eat its mutilated victims, it was merely methodically harvesting portions of their anatomy with which to adorn itself! It was simply doing what all decorator crabs do — snipping off and gathering bits and pieces of its immediate environment to attach to itself as a form of natural camouflage. It just goes to show, with crabs you can never be sure how things are going to work out…
So it’s hard to say whether your Emerald Mithrax helped hasten the demise of your female or if it was merely fulfilling its role as a scavenger, Mardean. If the Emerald crab had been acting aggressively toward the little female under the cover of darkness from time to time, it’s possible that this behavior was stressful to the female, which in turn allowed intestinal flagellates to gain the upper hand and become too numerous for her welfare, so it could’ve been a combination of things that weakened her.
At any rate, those are the only things that occur to me at this time, Mardean.
Best of luck with the rest of your seahorses! Let us know right away if you notice any other symptoms or signs of a problem.
Respectfully,
Pete Giwojna
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
