Fin rot is probably on of the most common bacterial infections that appear in aquarium fish. It is very easy to diagnosis fin rot because the fins are actually rotting away and will look as if they are dissolving down to the body of the fish. The fish tends to lie on the bottom of the tank because it is becoming difficult for the fish to swim.
The primary cause of fin rot is poor water quality. Stressed fish have weakened immune systems and that allows opportunistic bacteria to invade, causing fin rot. Since the stress is likely to be an environmental factor, other fishes are likely to be affected as well.
You need to find out what is the cause of the stress and remove it. There are many medications that you can purchase in your local pet store designed specifically to address fin rot. You will also want to do frequent water changes to help improve the quality of the water.
