The first thing you need to do is check your water parameters to make sure it's not a water issue.
That may be the problem. The flake foods could be stopping up the works which would explain the bloat appearance. In my angelfish hatchery I fed 3 times per day. I did flake food in the morning, a frozen meat food like blackworms or shrimps in the afternoon then a food like frozen or live brine shrimp or bloodworms or daphnia as a last feeding to clean out the first 2 meals. The 3 foods have a material in their shells called Chiton and that acts like a laxative to keep the pipes flowing. If he's eating them, I'd feed the bloodworms daily to make sure he's pooping then once that is resolved, use the flakes in the morning or first feeding then the bloodworms as the second feeding daily. If you add a feeding or food, do that as a first or second feeding but maintain the chiton foods as the last feeding of the day. I used bare bottom tanks in the hatchery so I could see if a fish was having digestive problems because every morning, I could see the poo on the bottom or on the sponge filters in the tanks. The sad thing tho is even tho my method worked on 99% of my fish, there was a few that got bloated that couldn't get healed. Those were probably the ones that did not eat the last meal to flush their systems. That's just the reality of fish keeping. The best you can do is give the fish the opportunity to be healthy. The rest is up to them. As the saying goes, " You can lead a horse to water but you can't make them drink. "
