I recently got some lobsters and they produce extremely quickly, I got 25 adults and about a month later I have hundreds of babies, all my darts seem to like them, except the thumbs which I haven't bothered feeding them to. Vaseline keeps them in there tub, keep them warm and they will do great, I have mine over a heat pad set to 88 degrees. If you need small roaches you can gather some of the egg cases and put them in a small container and wait for them to hatch, then feed from that container.