Diseases of Arowanas Below information is from the book "Jurassic Fish" by T.F.H. Bulging Eye Condition This is a common condition among Silver, Black, and Asian Arowanas, in which the upper part of the eyeball protrudes. The eyes of the afflicted specimen will continuously look down, but the arowana is tough and will continue to eat heartily. There are a few possible causes for this symptom, the worst being an infection from an injury near the eye. If this is not treated in time, it will worsen until the eyeball falls out. However, most bulging eyeballs have no observable cause, and the arowana can swim and live healthily with entirely uneven eyes. Sometimes the protrusion is caused by a fatty deposit, but this is hard to treat and should just be left alone. There is a specimen in the Toribane Aquarium with a bulging eye, but no other fish in the reserve tank has the same condition and the cause is still unknown. According to some arowana farm owner, when this happened to their fish, they simply put the fish back into the pond for a few months, and it will correct this deform naturally. Gill Curling When the covering of the fish's gills curls back to expose them, this may be caused by either a high concentration of nitrates or a lack of swimming space. In any case, this is a danger signal that must be heeded. The specimen is not in immediate danger of dying, but treatment should not be put off. Change the water frequently, create a more relaxed environment for it, and give it high-quality food. In short, take especially good care of it, and it should recover. Spinal Curvature This is most commonly seen in Silver and Black Arowanas. The causes are most often malnutrition when the fish is young and injury, but since the problem usually starts when the specimen is young, they need to be carefully checked for it before a purchase is made. As was mentioned earlier, the two Australian species are not as flexible as other arowanas and have to be kept in a relatively larger tank, or they may develop this condition. Once it develops, it is difficult to treat and a full recovery is virtually impossible. But if a decent environment is provided, this will rarely lead to the fish's death. Other Conditions Most other disease conditions and parasitic infestations are caused by infiltration of the tank by pests from outside, so care should be taken to check the condition of the food fishes and plants and apply disinfectants to them when necessary. The arowana is sensitive to fish medicines, so an ounce of prevention is worth many pounds of cure. Use any medicine sparingly and in conjunction with stepped-up regular care (water changes, etc). Even if the nitrite concentration is low, if the arowana lives a long time in high concentrations of nitrates it will become prone to curling of the gill cover and eye infections. Water purity must be maintained by using a large filter box and frequently changing some of the water.              © 1999                                                                                                                              HOME