I think one of my goldfish has something wrong with his swim bladder. He just floats around at the surface of the water, slightly leaning to one side, but isn't gasping for oxygen or anything like that. He also has some difficulty trying to 'anchor' himself to the bottom of the tank. I heard that feeding them peas could help, but please give me some more information, any help would be greatly appreciated THANKS

Cook peas. Squeeze gently to pop them out of their skin. Feed to fish. Number of peas depends on size of fish. Feed one at a time and don't leave uneaten peas floating in the tank.

Epsom Salts is also good if it is constipated, rather than a swim bladder problem. With swim bladder, the fish usually rights itself and is fine until it next feeds then the problem starts again.

also i've noticed that the fish only appears sick at night, and during the day he is perfectly normal, has good balance and doesn't hang around at the surface. is swim bladder meant to be 24/7?

Swim baldder problems can often affect a fish aftr it has eaten. Fancy goldfish are prone to balance problems due to their convoluted digestive tracts. They eat, the dried food swells up inside, and it takes a while for it to digest. While doing so, the fish develops balance problems due to intrenal pressure. Once the food as passed through the system the balance corrects itself until next time.

Some pellets swell up more when wet than others. It may be you are feeding pellets that are too large.

currently my affected goldfish is on a pea-only diet, and before that I only fed him small-sized flakes