Angle fish swollen stomach

Question
Hi, One of my angle fish seems to have a swollen stomach, it doesnt seem to eat and is not as active as it normally is. It also seems to have a few marks on its body,  I think this might have something to do with her fighting with one of my clown loach which is a little aggresive.

Do you know whats causing this?

Thanks.

Answer
The swollen stomach and not eating sounds like a constipation issue. Is your fish passing wastes and going to the bathroom? If he is not, I would definitely say he has a constipation issue. Full body swelling or scales sticking out like a pinecone could indicate a more serious problem called Dropsy. Your fish only has swelling in his stomach area so I wouldn't worry about Dropsy right now. Don not feed your fish for a day or two. This will allow him to clean out his digestive track naturally. If he is still constipated after two days, feed him the inside of a pea about the size of his eyeball. Do not feed him his regular food until this problem is over. We want his system to be cleared out. If the peas are not working then you may feed your fish daphnia, which  acts as a mild laxative. Constipation should cure itself as long as you are not overfeeding and are offering a proper diet. Also monitor your water quality to make sure you have no toxins such as ammonia, nitrite, and nitrate in your water. If you find you do, follow through with a water change. Hope he gets better!