Help with peacock gudgen

[Fizzler]

I had 4 of these guys. Recently one of them looked sick and wouldn’t eat. He is completely gone from my tank with no sign at all of dying. That being said while I did a water change this morning another one of them were dead on the bottom. All my other fish in the tank look great and very active. Idk what the issue is and why they died. I have two corydora, two amano shrimp. Clown pleco and a golden killi fish. And now only two peacock gudgen. One issue I’ve come across is with the feeding of the peacocks. I’ve tried flake food. Brine shrimp. Freeze dried bloodworms and mysis shrimp but the peacocks aren’t aggressive eaters so by the time the food reaches them by the bottom it either hits the substrate and they won’t touch it or they just eat one piece. Does anyone have any suggestions for what to feed and how to insure that they are eating enough? If they are dying of starvation I will feel like a absolute failure to them. I clean my tank once a month on the longest stretch and test my water parameters daily so it wouldn’t be ammonia that would be killing them. I hate losing fish I don’t add them to my tank to just look at, I try my best to care for them and give them what they need. So any suggestions or pointers would be greatly appreciated. Thank you in advance for your help!