I'm not sure about the male/female thing, but I'd probably buy another if I was you. IMO I would chage the positions of both the tail biters, so maybe if they had a new section to explore, they would be more occupied to have something to better to do ten to bite their tails.
Dime - Male - VT - Petsmart
*Aurorum - Female - TBD (To Be Determind) Tail - Petsmart*
Euphrates (Euphie) - Male - CT - Petsmart
Lapis Lazuli (Louie) - Male - VT - Petsmart