A 20 gallon long actually has plenty of space maybe not for two male mice but defiantly plenty of space I have two 20 gallon longs maybe you are thinking of a 20 gallon tall.

I have decied to go along with some females anyways

I found out my mom had a pet mouse when she was young (and she loved her mouse) so there could be hope of me actually getting some of these adorible guys or girls.

Thankyou guys so much for helping me.