White Coating on Puffer Fish Eyes

Cataracts

• Like humans, puffer fish can get cataracts. This condition also has similar causes in puffers, mostly aging and a lifetime of exposure to ambient UV light. This will cause eyes to get a milky look to them. If your fish are full size and you've had them for a number of years, cataracts are a good bet. However, puffers with cataracts can usually still find their way around with other senses. Like most fish they have an organ called the lateral line that helps them navigate by sensing the water around them. While you cannot treat or reverse cataracts in puffers, the condition rarely requires much treatment beyond making sure affected puffers are still getting their share of the food.

Infections

• A number of bacteria and larger parasites can cause infections on the eyes. Larger parasites can cause physical damage to the eye, much like cataracts. Often this damage remains even after the parasites are cured. However, if you see a slimy or fuzzy white coating on the eyes of a puffer fish, you can often treat it with over-the-counter antibiotics from a pet shop. These can usually cure bacterial infections. When the fish heals, the coating will go away, leaving the puffer as good as new.

Low pH

• Another cause of white coating on the eye is low water pH. Fish kept in such water often develop a cloudy coating on their eyes. Research your specific species of puffer fish, since different species have different pH preferences. Keeping up on your regular water changes will usually increase the pH of water enough to prevent this problem. However, if your local tap water's pH is low, you can also add buffers from pet shops to raise the pH. Never raise the ph by more than .2 per day, as sudden changes in pH, even changes towards ideal conditions, stress fish out worse than keeping them at the wrong pH. This type of eye problem will usually clear up quickly once the pH is corrected.

Overcrowding

• Overcrowding can indirectly cause clouding on the eyes of your puffer fish. Freshwater and salt water have different stocking guidelines̵2;1 inch of fish per gallon for freshwater or 1 inch of fish per 2 to 4 gallons for salt water. However, for puffers larger than 3 inches, these guidelines break down, so research your specific species to find out how much space it needs. Overcrowding makes it more likely that ammonia will build up, poisoning and stressing fish. This can also drop the aquarium pH dangerously. Additionally, many puffer fish are territorial, so crowding them produces fights. Stress leaves fish more prone to disease, which can spread rapidly in a crowded tank. Both lower pH and the stress of a too-small tank promote various conditions that can give puffers' eyes a white coating.