[Cougra]

White Cottony patches are a bad sign. The best way we can help you is if you get a picture of the fish as soon as possible. Time is very important since there are some diseases that can quickly infect every other fish in the tank and can kill in periods as short as 24 hours! Also, describe the symptoms as well as you can including how long the fish has had it and if any other fish show ANY abnormal behaviours. Also, what are your water parameters? How long have you had the fish? When was the last time you added ANYTHING new to the tank? The more details you can give the better!

A couple diseases that come to mind are Brooklynella (Clownfish disease), and Amyloodium (Marine Velvet). Both of which are extremely difficult to treate and highly infectious. I've lost 8 out of my 9 fish overnight to a case of Marine Velvet within three da

If you are lucky it could also be something easier to treat such as a type of fungus or bacteria. If it's on the fins or near the base of a fin, chances are it's a type of fungus and should be treated with a fungicide type treatment outside the main tank. If it's found on the main body not near the fins, especially the mouth area, chances are it's a bacteria (known as Columnaris which is often erroniously refered to as mouth fungus because the symptoms look similar to fungus) and needs to be treated with an antibacterial remedy. Both these diseases can be fatal as they weaken the fish and attack the gills. If treatment is given soon enough then there is a very good chance for recovery.

Once you figure out what it is, the fish should be removed from the tank before treating. If at all possible treat all the fish in the tank, however if you can't get them all, make sure that you treat the ones with any signs including loss of appitite, poor colouration, hiding more then normal, lethargic or breathing more rapidly then normal.