The Crabs In Pets At Home

[Corleone]

They need more land than water, something like boboboy's pictures show. They're very good escape artists, and if they don't have enough space to move around on land, they'll find it, even if that means it's your living room rug. As already covered in this tank, they need brackish water, which your neons won't like, the guppies and shrimp don't need but probably won't mind, and the bottom feeder... well, depends on what species it is.

Because of the setup they need, there wouldn't enough water for the fish in the same tank, and it would just be a gamble on how long before the crab starts picking them off for a snack.