I have 2, 3 or 4 month old leos and one of them on occasion will bite the tail of the other, is this anything to worry about?
The one that bites is slightly bigger than the other.
The bites are small nips that don't leave any marks.
geckos are not social animals in the wild, they are solitary. in most cases you can keep groups of females together, and some have even said they've kept males together. none of that is relevant though to your situation. either you have a male and female and the male is trying to mate, or you have two geckos that are not compatible. either way, again they need to be seperated