01-04-2010, 01:19 AM
| || |
My first question has to be, what size tank is this? In answer to your question, based on the information provided, the answer is that it could be either of those 2 things... or any of a whole list of other things. Can you post a clear photo of the fish that clearly shows the problem you are concerned about?
If there is a possibility of infection, especially something as highly contagious as fin rot, I would not suggest adding more fish until you know for sure. Any fish you add, you not only risk exposing them to illness, but you also risk exposing an already possibly sick fish to further illness that the new fish can bring in.
Do you have a quarantine tank? New fish beyond the first fish to a tank should always spend a minimum of 2 - 3 wks in a quarantine tank to help avoid spread of illness, and to allow ease of treatments when needed.
I am also wondering how much decoration is in the tank? How is it decorated? A photo of the whole tank would help alot for that. With their aggressive behavior, tiger barbs do best in very heavily decorated aquariums where a weaker or less dominant fish has the ability to easily hide from tank mates. If a fish is being bullied by a stronger tank mate, it is likely going to find a "safe spot" and stick to it. If not enough decoration is present to break up territory in the tank, whatever fish has claimed a large territory will usually ward off any other fish who attempt to enter it, leaving other fish to smaller areas to safely call their own.