Thanks, Tom. I ask because I have one of the largest ones in the group digging a pit in the front center of the tank. Its colors are dark and it's chasing away all the other fish. I do see tubes half down on a few of them. It doesn't appear to be flirting or pairing with any of the others; it's just digging alone.
It's an interesting behavior because since I bought them I haven't seen them do anything except fight and eat.
It's an interesting behavior because since I bought them I haven't seen them do anything except fight and eat.