If you're going to keep them in the main tank, try using marbles (although someone had a problem with that because they chipped, but I never). The round type, not the flat type. And you need decent sized marbles, not the smallest kind. Pile about 6 on top of each other and the fry will hide in the gaps between the marbles. Looks really cool too. Here's a picture:
http://www.fishlore.com/Forum/8-bree...for-fry.0.html.
They also like to hide in hornwort (plant). It's a very hardy plant too, and the big fish loves to nibble on it. They also like to hide near the root of big leafed plants.