You make it sound like you feel they're not getting all they need from NLS. They're carnivores, so you can feed them lots of different things, but really don't need to. At least that's been my experience.
Yea, it sounds like that lol,I did not mean to ask that way...
I read in different articles that hobbyist feed their fish with variety of food, so before I offer anything to my fish, I always ask around.
My melegrise (pearly occelatus) eat anything I put in the tank. Their staple is NLS pellets. I feed them other things more for my benefit than theirs I think. I just enjoy watching them eat different stuff For example, white worms, blood worms, mysis, mosquito larva, flakes. I'm no expert, but I agree that NLS or another high quality product is probably all that's needed.
Variety is definitely more for my sake. I enjoy watching how all my fish feed differently.
I'm currently doing frozen brine shrimp, frozen blood worms, and pellets for my pearly occelatus. I have some Ken's flake coming that has brine shrimp as the main protein source so I can stop buying the more expensive frozen stuff and just save that for a treat (I usually spoon just a few in at a time so it is more of an involved process which is fun).
My mbuna go absolutely nuts for crisps. Several of them attempt to horde the crisps in their mouth and then they get run down by other fish and their crisps get stolen. Its like fish bumper cars.