i spoted it in the second vid the gil flaps are realy big but it also has gill curl you can see it when the fish terns to the left the gill fold right up. and judgeing by the way the fish is swimming that tank is a 125 or 220
Little RTCs hide. When they get as bigger, they loose interest in hiding and gain much confidence, IME and from what I read of others. I think the "apparent" shortage of swimming space verdict may be warranted but again, no full tank shot.
I agree with the gaining confidence with size but they are abmush predators, meaning they hide. Just about all catfish with that body shape, that I am familiar with, are ambush hunters and if given the option, will always hide under a fallen tree or similar as opposed to laying in the open. I didn't see the gill curl til liontammer pointed it out, unusual to see it on one side and not the other. Would like to see a pic of the right side of the RTC while at rest.