They could've been intimidated with no hide and bigger fish hovering above. That's the only thing I can see making them behave differently
I hypothesize it's their nature when adults. They were the same listless fish in various communities even where they were the biggest fish, when older. Nor have I observed any sign of comprehension of danger from bigger predators or any bigger fish. No avoidance. No nothing. The only thing I've seen them do is fight a bit among themselves. Other than that, they have a personality and behavior of driftwood. This is barely an exaggeration as the wood doesn't feed, while these guys sometimes fed when feed fell on them or in front of their snouts. That plus a rare fight is pretty much the only difference between them and a log.
