A 125 is a bit small for more than 1, or a compatible pair of them. I had a group of 6 that whittled down to 2 in a 150. At 6" the male started to try to kill everything else in the tank, he ended up alone in a 55.
He had a young 10" managuense pinned in a corner.
He had a young 10" managuense pinned in a corner.