Can you keep animals in the sump

[Llyod276]

I put a 6 line in my sump on purpose to eat all planaria he can plust what ever else is down there... Just because there are so many below. Got 3 peaceable types up top, and I've always liked 6 lines, but know they are jerks... so he's in solitary and he seems to love it... finds swimming through the macro a challenges. Literally looks like he's crawling through it...