They are good to go for fasting right now. I always fast mine from day one once I figured it out. I start off with frozen blood worms. Seems to be like crack for baby catfish. Usually as soon as I put them in the tank they will eat it from an eye dropper. Just melt the cube in a cap with a little warm water, then suck it up with the dropper. Put right in front of the catfish mouth and squeeze it out. Wish I had a vid of when I had my tiny, tiny baby catfish sucking on an eye dropper like it was their baby bottle lol. After they got fat and happy off that for a few weeks I always moved on to frozen krill, and from frozen krill to chopped fresh shrimp. THen I will start trying to get them to take floating cichlid pellets from the top. Usually doesn't take too long. Hardest one by far was my filamentosum. Got to cut out the feeders all together, and don't put a single one in the tank. Wait a few days after the last feeding and do a tank cleaning. once fish have settled down that night add a couple cubes of blood worms and see if they take too it. THey should have frozen blood worms at your LFS. If not then the store is crap and find a different one. Even turn out the lights except a distant one so that you can watch them take it the first time. Let me know how this works. Usually does the trick for me every time.