Pterophyllum leopoldi

Hi I got from a friend 2 of these. He bought them together with some big SA ciklids. Where they did not feel good.
Ok one died straight, and one I have now for about 2 months.
But: I do not really see what he is eating, maybe nothing.
anybody have an idea about some delicius food to give him ?
I feed him frosen red worms, white mosquito larvaes, black mosquitoes, artemia, a beafheart mix with much fish and shrimps, and some dried food. It seems like he likes the normal dried food best.
He even don`t really seem to care about Living daphnia ?
He now goes with some Manacapuru scalares (recently) just to get some compani. They are about he`s size.