I thought so too. But after observing him so long he never moved his own dorsal fine nor his tail or back end at all. his little side fins were like humming bird wings the whole time.Maybe injured his swim bladder during the drop or whatever happened during shipping.
A lot of water “under” the bridge so to speak. I first installed a preformed pond dabbled with that a few years and a fountain then dug a bigger hole and used a double liner and installed a uv sterilizer and an underground channel for the waterfall. These fish like to jump up onto the bank to feed so they try to swim up the fall which is hilarious to watch. Yesterday the five little ones followed the big daddy around to learn how to skim the edge for food.Such a good stream of water from that waterfall! How’d you figure that out? Seems tricky to dial in.