Fin Rot HOWTO..

Fin Rot HOWTO..


By Jim E. Quarles

This seems to be a problem that beginners encounter far to often because it is totally preventable. But once it hits your fish action is needed quickly to end the problem. That is the reason for this short article.


There are a number of bacteria that can cause fin rot, the most common being one known as the genus, Cytophaga. This disease factor has been called many names, Chorndococcus, Cytophage, Fexibacter, Myxobacterium, once even known as Flavobacterium. The most common species is columnaris.


The cause of this disease is well known, and has been noted by fish keepers for years. Columnaris organisms are a normal part of the environment, they have been observed feeding on uneaten fish food, and most likely feed on organic wastes common to a fish tank that is poorly maintained. What is important to note is the numbers of bacteria that are contained in a given volume of water. When these numbers increase, any stress factors subject the fish to the onset of the disease. It is well know that stress in fish reduces resistance to many diseases.

The onset of the disease is preventable. Keep a clean tank with frequent water changes and you will rarely see this disease on the fish.


If the fish show signs of open sores on the body, that rules out the use of formaldehyde, since that might kill the fish if it enters the fishes system via direct blood contact. The use of copper sulfate could be used, but I don't recommend it because the dosage level must be tightly controlled and this is beyond the skills of most hobbyists.


Kiss stands for " keep it simple stupid." Many people will tell you to use this anti-biotic or that anti-biotic. The use of antibiotics should be a last ditch resort, not the first.

A very simple and effective way to cure simple fin rot is with the use of common Rock Salts. The kind you use for making home made ice cream, or found in water softeners.

The only other item that should be used with it is a dye known as MALACHITE GREEN. DOSAGE: 1 drop per gallon. With frequent water changes over three or four days. As you replace the water add back half the dosage, or one drop to two gallons of water and don't for get to use one teaspoon of Rock or Sea Salt per gallon. This also should be added back as water changes are made at the dosage.

I have seen just about every suggested cure and cause named on talk forums and other sites of information. I would recommend to any hobbyist that such advice should also be taken with a grain of salt or two. Ha ha.. A good book is your best source of information about most fish problems not second had rumors or old wives tales.

One other note. If you can cure the disease before it gets to the fin root of the fish the fins will grow back and should be normal. Once the disease reaches the fin root and damage occurs it is unlikely that the fin will ever be replace or normal again.

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