I need help! should i seperate my axolotls untill they are one even though they have been togeather since eggs?

i have a 2 ft tank 65L and im looking at getting 2 axolotls two female. the ones im seeing at buying are 2 inches long and have always been housed togeather. ive been told they should be seperated untill 1 otherwise they will always nip at each other. the ones im buying there are 15 at 2 inches long all in a 2ft tank, should i buy theses or not as i dont want them munching at each other!??!