Try conditioning them without live foods and see if that works. Mine spawn a few times a week just eating things like Hikari Vibra Bites, black worm pellets, freeze dried tubifex worms, Northfin Bug Pro, etc. I make a mix in out of this and feed it 2x a day.
I think the key is quality foods, not necessarily live. But yeah, you can't go wring with live foods.
I feed the fry BBS and, as they get a little bigger, grindal worms, eventually switching them to flake. So, no real recommendations on what is good that can be harvested from nature. But a good, quality flake food, crushed up, will work as well.