Pimple like sore on tail?

Is that an open wound next to the red pimple? And it also looks like a scrape or bruise along the mid section of his body. Could this fish have gotten stuck behind something? Like the heater?
How about aggression between any of the fish?

I'd keep up with the water changes--try doing them daily or every other day. If the area doesn't look better in the next 24-48 hours then I would remove him and treat with an antibiotic.

Robin

No, there is no open wound and there is no scrape. He just looks like that. He is in there with a baby frontosa and a pleco. He is the aggressor and he is 6" long. The next biggest fish in there is the pleco at about 3".

EvoFish said:

No, there is no open wound and there is no scrape. He just looks like that. He is in there with a baby frontosa and a pleco. He is the aggressor and he is 6" long. The next biggest fish in there is the pleco at about 3".

Click to expand...

Must be just how it looks in the picture as it looks like he's got some scales missing.

The bump may be some type of viral infection or a tumor, neither of which have a reliable cure. Fish Pox is a viral infection that gives the fish waxy white, pink or gray growths on it's body. Improving the water conditions and keeping the temp up between 80-82 may help. THe pox should gradually disapear on thier own unless the tank conditions are really poor.
Another common viral infection is Lymphocytis. Again, no known cure but improving water condition and isolating infected fish to prevent infecting other fish is a good idea.

I don't know for certain what your fish has. Do what you can to improve water condtions, (daily water changes) and keep a close eye on the spot to make sure it's not getting larger or changing in any way.

Robin

Thanks for the reply Robin. It seems like his zit is getting smaller and flaking off. Now there is only a red mark there. Hopefully it will go away fully.