Dwarf Piscivores

so ive been doing my research on try to find a small predatory fish to help cull fry in my tank.

ive scratched off NeedleNose fish, too big(im gna hv cardinal tetras); exodons, too aggressive; dwarf pikes, too competitive.

and so ive narrowed it down to Leaf fish and Belonesox, although im leaning towards the leaf fish.

anyone have any opinions or experience?

i have some of the african bush fish/ leaf fish, i love them there personallities are awsome. they get about 4-5 in so when they got a little bigger i dont know if id keep them with the cardinals

anything tht stays dwarf size? small enough to not eat cardinals, but voracious enough to snap up lil fry?

maybe ill rescue a cruddy looking shortfin male betta. hopefully he wont be dumb enough to get in a scrap with any of my dwarf cichlids. if hes at all intelligent after a couple beatings (which is bound to happen) he'll stay up top hidden in the floating plants. i think this is the route ill have to take, cuz the livebearer babies are getting wise and not going anywhere near the bottom where the dwarf cichlids are.