I have 6 angelfish in a 55 gallon tank. About a week ago, one of them started having swimming problems and I noticed a bulging stomach. The "guy" at the pet store said it was probably swim bladder disease and that there is no cure. Well, I just don't give up that easily. About a week or so prior, I added 3 new misc community fish--2 died within 2 days. So, I thought maybe there was something that my angels caught from the new fish and that since the "sick" one was one of the two oldest that it was just the first to show symptoms. So I started with the 25% water changes everyday for 5 days. His swimming just kept getting worse. After researching on this site and others, I found that it could be a number of things and so I started trying different things to "cure" my fish. Maybe it was constipated and that was affecting its swim bladder? He hadn't eaten for a few days already so I fed them a few squashed defrosted frozen peas. I also gave them some of their flaked food soaked in castor oil, as well as some frozen blood worms. At the same time I have been treating them with Maracyn Two. Then a few days ago my angelfish that was literally laying on its side on the bottom of the tank was now up and swimming around perfectly with the other fish. A miracle I thought.
Now, it is hiding in the plants "nose up" then comes out and swims around perfectly, then goes back into the plants for awhile. In the meantime, 4 others hover over the plants and the 5th angel stays on the other side of the aquarium. In fact, when the lone angel on the other side tries to come over to the side with all the other, the 4 angels hovering over the one in the plants chase it back. In fact the only one that seems to be allowed to swim in the whole tank is the one that comes out from hiding in the plants and swims around and then goes back to hiding--nose up.
WHAT THE HECK IS GOING ON? IT SEEMS LIKE ONE IS BEING SHUNNED AND THE OTHER IS BEING GUARDED.