I currently have 1 juvenile BN (1.5inches) in my 20UKG community set up. A friend is moving house and has another juvenile of approx. the same size as mine in his tank... he has asked me if i'd have it... I like BNs and would like to house his... but they are both too young to tell if they are M or F... will two males be ok in my 20UKG or will they fight...