My angelfish that I have had for 1.5 years has not been eating for 2 days. I wasn't too concerned, as he often doesn't, but yesterday I noticed was isolated in the corner of the tank. Today he is floating around listlessly and appears to be having difficulty maintaining a vertical plane. His stomach also appears to be bloated. None of the other fish are bothering him. The only change that I can think of is having frozen bloodworms the other day for the first time in a couple of months, but he used to eat them before (same package) without problems. There are also some dark spots on the anubias that have appeared in the last week.
I have had a 30 gallon tank for the last 1.5 years. It has not had any changes for the last 3 months. In it I have 8 neon tetras, 2 dwarf gouramis, 1 boseman rainbow, 1 large angelfish (the sick one), and a small (young) angelfish. I also have about 9 large live plants. There is a gravel bottom, and hiding spaces made out of rocks. I don't have the water parameters because I lent the kit to a friend. I do 25% water changes once per 2 weeks.
Any help would be appreciated