I have a 20L sitting empty right now but we were going to use it to seperate feeder mice by sex. Currently we have 13 feeder mice and soon they will all need to be seperated so they will concentrate on getting big rather than breeding. I could possibly pick up another tank and set up two females to grow them up. Will a lone male be ok in a 10g until I can grow up two females for him? By the time everyone is old enough to breed, I should have the rack built.