Seahorses are prone to species specific diseases. Here is a list of possible diseases a seahorse can get and there treatments. Pouch emphysema: pouch emphysema can be traced to decaying mater in the pouch, producing gases and causing the pouch to bloat and or physical air bubbles in the water column entering the pouch. Treatment of this is to first determine the problem. Check for air bubbles from power heads or your skimmer return. If there are no bubbles make sure the tank size is at least 3 times the height of the seahorse. This will allow ample space for the seahorse to exercise and flush out its pouch. For immediate relief you can manually remove the bubbles by gently rubbing the pouch with your fingers in an upward motion. For a recurring problem u can use an antibiotic neomycin does a good ob of relieving this. Internal gas bubble disease: this is caused by gas supersaturating or a bacterial infection. Usually when a seahorse gets this it’s very hard to treat and most times very fatal. The seahorse starts to bloat and makes it very hard to maneuver almost acts like a buoy. The only way to treat this is to put the seahorse in a tank that is at least 3 feet deep. You need to keep the seahorse at the bottom of the tank for several hours to decompress. U can also try injecting the seahorse with acetazolamide. External gas bubble disease: these are air bubbles just underneath the skin that cause the seahorse trouble in swimming ultimately causing much stress. This is generally caused by air bubbles in the water column. To treat this disease u can use a sterile needle into the gas bubble to lacerate it and evacuating the gas. Or the best treatment would be diamox baths Pop eye: pop eye can be brought on by internal fugal infections are parasitic infestations. The eye itself will protrude from the socket damaging the organ, if not treated immediately it can be very fatal. The only treatment that won’t actually kill the horse would be to use an internal parasite medication such as niclosamide. External parasites: Macro-parasites such as flukes and isopods can be seen with careful examination. However, often they will take on the coloration of the host, so you may be looking for odd bumps on the fish, rather than the telltale signs of the organism itself. Micro-parasites such as Cryptocarion irritans and Amyloodinium ocellatum rarely attack seahorses, assumedly due to their tough, but thin, skin not providing enough depth for the parasite to insert and incubate. Other micro-parasites such as monogenetic trematodes are far more common in seahorses. Symptoms include cloudy eyes, erratic swimming, flashing (scraping on the rocks, decorations, or substrate), rapid breathing, weight loss, and listlessness. Parasites, once given the chance to get a foothold can cause a terrible death for your fish as they sap the energy and vitality from their host like little vampires. When treated with the proper medications, this pathogen can be completely eradicated and the fish can experience a complete recovery. Treatment for this should be first treated with a freshwater dip, then formaline a dip, and finally the best, but most dangerous solution, Trichlorfon highly toxic to marine fish and deadly to invertebrates. Internal parasites: Internal parasites are typically organisms such as trematodes (commonly called "flukes"), cestodes (commonly called "tapeworms"), or nematodes (commonly called "roundworms"). These organisms usually attach at some point along the digestive tract or liver of the host animal by use of a sucker or a rostrum (hook-like proboscis), feeding off the incoming nutrients, blood, and tissue. This prevents the host from obtaining appreciable nutrition for its meals, resulting in a gradual wasting, and oftentimes in complete refusal to eat, assumedly due to discomfort. Left unchecked, these parasites will literally consume the host animal, leeching vital nutrients right out from under it, causing tissue damage, hemorrahging, and eventually death. metronidazole is a good first choice medication as it is very safe to use, not effecting the bio-filter or invertebrates, and almost impossible to overdose with sensible usage.