Review on Pawfly Fish Breeding Box Tank with Hatchery - Ideal Aquarium Incubator and Isolation Solution for Baby Shrimp and Guppies by Veronica Wade

I have only placed guppy fry there, no pregnant guppy but so far I like the fry. The gaps are large enough to allow water exchange, but small enough that the juvenile fish cannot escape and the adult fish cannot enter. The roasts are clearly visible through the walls of the box, which is nice. The suction cups also seem to hold it securely to the tank wall, although I do make sure to press it back against the wall after each feeding/lid removal just to be on the safe side.