two terrapins in a tank, one flicks other ones eyes

by Sinead Egan
(Dublin, Ireland)

Hi,

I hope you can help me out, Iv had two terrapins for years now, I have them in a large aquarium and they ahve always interacted well in the tank. One is substantially larger than the other. The larger one has lately displayed some troubling behaviour!!
He swims driectly in front of the other, so that he is facing him. He then stretches out his arms/claws and flickers his claws into the other ones eyes!! It looks so awful for the other terrapin, and he is constantly trying to get away for the bigger one. Im not sure what the behaviour is showing, is it a display of dominance??
Please help me

Sinead