My baby fish

My baby fish had so much food last night and I found them dead this morning :( They ate so much and had big tums and I was so sad to see them dead today. Only one made it (I think it was the one on a diet). The water is good as I change the tank water every week and the other big fish in the tank are doing really well so it seems that "childhood obesity" is not only a problem in primary schools but also for the fish. I had a lot to do today clearing away the small dead baby fish and cleaning their small breading box. The good news is that one of my female guppies is pregnant and will soon have some more babies. Will put them on a strict food routine straight away.