I use them for my baby bettas, but you cannot feed them to large bettas because they are too small. If you want a culture I can give you one for a small charge.
I think they are awsome for baby fish! I have fed them to baby guppies, platies, and Bettas. They LOVE them! The thing I like the best is they are sooooooo easy to keep. Every two weeks a whip up a small batch of oatmeal and add some worms from my past culture and within a few days I can start feeding.