I get a variety pack of frozen food from one of the aquariums in Edinburgh.
It has blood worms, a favourite, brine shrimp, daphnia and white mosquitos in it.
Last weekend when I was in I noticed that they are now selling live bloodworms and brine shrimp so I am thinking of giving that a go.
I give him squashed peas and brocolli once a week as well.
The honest answer is that the wee guy would eat pretty much any food that goes in the tank.
I also got some dried betta food, he did turn his nose up at that for a while. He is also partial to catfish sinkers I got.