Well the females are all ~210-230g and the males are ~250-300g. Since I hadnt read your reply yet, I put 2 of the males together and left the room for a few minutes. Upon my return, I noticed the larger one bullying the smaller one and his leg was bloody. I dont have the room to seperate all of the males and have a spare tank for the females. is their current weight close enough to the 250g or should I just try to find an extra tank somehow? I could probably put 2 of my normal balls together to make an extra slot for rats... Btw, to keep some part of this on-topic, I know you said nutro cat food was no good, but what about the dog food? Its pretty expensive and the protein on the senior food seems to be in the right range. Would it be good to mix into their diet? If I am ruining the thread with all of these questions, just pm me instead. Thanks!