What Is Fin Rot?
When you see a case of fin rot you will always be able to recognise it. It will cause a discolouration at the site where it happens, and this discoloration on the fins will spread if left unchecked. The fin will keep rotting away and in worst cases until where there is only a stump left where the fin was.
Attacking Fin Rot
Fin Rot is caused by bacteria that is always in the aquarium water. Under normal circumstances, fish can ward off the bacteria and will not get fin rot. When this happens, there is usually something wrong in the aquarium that is causing stress to the fish inside. Some examples of such stress can be spikes in ammonia, nitrities or nitrates, introduction of aggressive fish, that caused stress or physical injury to the affected fish. Think of it this way, when you get a cut on your skin it usually heals by itself and not get infected right? This is the same for fishes too. When their immunity is down, it is usually caused by something that happened to their environment that they live in so try to pinpoint the cause and deal with and the fish can recover by itself. Main thing is to ensure the water is in its best condition with no nitrogenous waste and add some salt in the water for anti-bacteria effect. If there is a scar after healing and it is near to the edge of the tail fin of a big fish, you can bag it and use transmore to make the fish sleep before you carefully trim it away with a pair of sharp scissors (ONLY trim it around the affected edges, NOT cut the tail off!!). If it is the side fins you should not trim it because it can give the fish difficulty swimming before it grows back.