Symptoms: An ulcer is defined as a break in the skin extending through all the layers, which fails to heal and is often accompanied by inflammation. The typical skin ulcer has a central area of tissue erosion that may be shallow or deep – in many cases exposing the underlying muscle. Around the edge of the lesion is usually an area of whitish necrotic (dead) tissue and debris, with a large outer zone of inflammation extending into healthy tissue. The scales surrounding the lesion may be raised or infected. Without treatment it gets progressively bigger. In most, but not all, cases they are caused by opportunistic bacteria already in the pond or tank.
Causes:
They can be caused by damage to the skin from parasites or chemicals (for example exposure to high levels of ammonia or nitrite or high/low pH). Fish can also be susceptible if their normal defences are compromised by stress. High numbers of opportunistic bacteria, such as would be found in water with a high organic content or other diseased fish, also increase the risk of infection.
If just one is affected it is probably due to a health problem specific to that individual. However if several are affected it is quite likely that there is an underlying environmental problem. In this quite common situation it is no good simply throwing in some anti-bacterial treatment and hoping. It is important to establish and resolve the underlying cause, be it water quality or parasites, as well as treating the bacterial infection.
Treatment:
It is hard to give a general answer because it really depends on the circumstances surrounding each case. If just one individual is affected and assuming that it has been diagnosed at an early stage, simply dealing with any other health problems and treating the lesion topically may suffice.
If several are affected it is vital that the system and all of the fish are examined, either in or out of the water, to determine the full extent of the spread of the infection.
My own experience is that the chances of survival are greatly improved by a thorough debridement of the lesion together with topical treatment. This is an important step irrespective of any other treatments used. Copper Safe, General Cure, Maracide, Aquari-sol, are also considered possible treatments.
