Ted Judy gave a great presentation on raising fry and I thought that I'd share my main technique and see how others do it. Unlike Ted, I mainly raise decent-sized fry (cichlids and livebearers - no African Butterfly Fish, Rainbows, or tetras ). For raising and growing out fry I primarly use 2'x2'x1' tanks, which are about 33g but have a lot of surface area. I have a sponge and a box filter on each for filtration. No substrate and maybe a plastic plant and a flowerpot for hiding spots. I heat the fish room as opposed to most tanks, so the water is about 76-78 like most of my tanks. All of the tanks in my fishroom receive generous tap water changes, so all of the tanks are very similar in water characteristics. For mouthbrooders, I generally allow females to hold for a couple of weeks in the main tanks, catch them and place them in a net breeder in the fry grow out tank. I keep an eye on the females until they spit and then I take them out of the net breeder and put them in the grow out tank itself. The fry in the net breeder receive all of the benefits of the main tank (water volume, filtration, etc.) but are easy to feed (the food density principle that Ted talked about). I generally feed ground flake and high protein floating pellets (which they can pick at all day while I'm at work). Their mother can eat any food that the fry don't as it falls from the net breeder into the tank. After a few days of recovery, I put the female back in the main tank, where she can breed again. I can keep several batches of fry growing out in the same tank with this method. And as the fry get to 1/2" or so (too big for the net breeder), they're easy to transfer to their own tank (simply move the net breeder to another tank and dump it). For substrate spawners, I prefer to let the parents raise the babies. If it's a fish that I really want to make sure I get some fry from, I siphon some wrigglers into a critter keeper (1/2g plastic tank with a lid) and leave some for the parents to raise. I drop the critter keeper into a 2x2x1 tank...and wait for the babies to become free swimming. They generally stay in the critter keeper, which is easy to drop food (crumbled flake, frozen baby brine, etc.) into. Eventually they start to swim out and I dump the rest out of the critter keeper. A key, I've found, for keeping substrate spawners fed (when I work from 7 - 6 or so) is to have a mature sponge filter in the tank. I also keep a box filter bubbling.