Common fish health problems

Aquarium fish diseases weaken fish

If you regularly maintain your tank and only keep species that get along well together, there's a good chance your fish will live out their lives in optimum health. But stressors, mostly due to poor water conditions, can easily weaken their immune systems and they can become sick. Symptoms of illness in fish include lethargy, fungus, damaged fins, white spots on the body, impaired swimming, bloated stomach and appetite loss. A discussion with your veterinarian, isolation of the sick fish in a quarantine tank, and medication, if necessary, can help your pets get back in the swim of things. 

Fin rot and its causes

The symptoms described above are indicative of some of the most common fish diseases. Animals suffering from fin rot, for example, may have frayed, whitish-looking fins. Fin rot can be caused by fungus or bacteria, and often follows injury caused by a fin-nipping tankmate. Fish who live in poor water conditions often succumb to this disease, which may require
antibiotic treatment.

Although experts don't agree on what causes it and how to treat it, DROPSY is less contagious than other diseases--and more likely to be seen in gouramis and platys than other species. Affected fish swell up like balloon, and possible treatments include antibiotics.

Ich is one of the most common fish diseases

Triggered by a deep-burrowing parasite, ich--also called white spot--is a highly contagious and all-too-common disease that causes small white pustules on a fish's skin and gills. Affected animals may rub themselves against objects in the tank in an effort to stop the uncomfortable itchiness. Treatment involves isolation of the sick fish and medication.

Poor water quality causes many tropical fish diseases

Another often seen ailment, though more difficult to cure, velvet, also called rust--first affects the dorsal fin and then the entire body. Fish afflicted with velvet look as if they have been dusted with amber-gold flecks and may display a shimmying movement while swimming. This disease is treated with antibiotics, though the old-fashioned cure involves dropping a few copper pennies into the tank.

If a fish gasps at the surface of the water with his fins held unusually close to his body, he may be a victim of bad housekeeping. Poor water quality accounts for the vast majority of illness in fish. Incorrect temperature or pH, for example, or too many toxins in the water, can place unnecessary stress on fish, increasing their susceptibility to sickness. And while pathogens may always be present in the tank, fish with weakened immune systems cannot fight them off. Aggressive tankmates can also stress fish out, so it's crucial to select species that get along.

If you suspect that one of your fish is ill, it's best to quarantine the individual in a hospital tank and work with your veterinarian or aquarist to determine a treatment protocol. And we can't stress it enough--the most important thing you can do to ensure the health of your fish is to clean the tank regularly. That means replacing at least 10-25 percent of the water at least twice a month, and conducting periodic checks of the ammonia and nitrite levels in the tank. Preventive medicine, after all, is the best medicine.