D.gilly's 20 gal shellie tank.

I'd add about 2 dozen more shells if you really want a good habitat for a colony. The fry will swim among the shells when they grow large enough to feel crowded inside the spawning shell, and having plenty of cover will increase their chances of survival as well as make them feel more secure. You'll also need more shells when the fry grow out. Females will establish thier own pecking order, but males will be chased off my the dominant breeder.
 
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