Thanks for the replies everyone.
Yes I appreciate they will eat anything they can fit in their mouths and in that regard the same as any predator and the fish I already have. The grouper will absolutely eat anything it can fit in, sometime items it can't ��.
Xkon, it would seem would seem there is an issue with territorial aggression with other eels, although in your expearence mild? There is a risk. I will give it some thought. Out of curiosity how big where they before you moved them into your 135?