I have a 5.5 gallon aquarium that is split with two bettas and some ottos. One betta kind of floats on his side. He seems fine other than that. He eats, but it seems as if he can't swim straight. Sometimes he'll act like he is stuck in the plants, but he really isn't stuck. He did have ick a couple weeks ago, but I cleared that up. What could be wrong? He has very long fins, is this a sign that he is old? Could it be swim bladder disease?