I do use Hikari gold daily, but i regularly throw in mussels, prawns, crickets, worms etc for my catfish. Of course my cichlids get a taste of everything. Problem is that the Midas out-muscles all the others for first dibs on anything that gets dropped in the tank. I have had no noticible problems so far but after reading about the wrongs of a high-protein diet I was concerned about any internal problems that may be caused.
When I had a midas I fed mostly hikari gold pellets. She would lose interest in most other foods after a time if I fed them too often. I would say stick to the pellets and then once in a while put something else in as a treat. She did seem to like shrimp pellets a lot though. But only as a treat.
i initially fed mine tetra prima but i swapped to hikari cichlid gold as it doesnt crumble as much in the tub and satys whole. i also use earthworm pellets, spirinula pellets, frozen bloodworm and im using up my hikari algae wafers as i dont have a plec yet.
Use a mix. I like to use Hikari Gold and Excel. That way he gets a mix of high protien and a mix of a veggie based diet. Also krill, pea's, earthworms, shrimp, and algea waffers.
I always feed my fish a mix of food but I had a 7 year old Midas in a solo tank and ALL he would eat is Hikari gold. I belive this diet caused him to develop HITH, my water parameters was perfect. Now I make my fish eat a large varaiety of food. If they dont eat it, then they go hungry till the learn to eat it. Now all my fish in all my tanks eat everything I provide. Heck, they eat better than me on some days.