I was playing Minecraft bedrock on a realm and had made an underwater sea pen. It is made out of waterlogged spruce fences and was large (I will include a picture of the error).  Before I detail the bug, I must note that, while I was playing on the Xbox, the realm owner was playing on an iPad. This may be irrelevant, but another member of the realm played on a Nintendo switch but was not playing at the time I noticed the issue.

       I had expected the fish to just swim around, the axolotls to kill the fish, and the dolphins to swim playfully. Instead, I noticed that all the fish and axolotls in it had, as it appeared, stuffed their heads in the fences. The axolotls made no move to kill the fish in the tank after they had put their heads in the fence. They also made no move to attack any of the drowned in the pen, even when struck with a drowned trident. I later moved a dolphin in, and after swimming for a few seconds, also got, as I believe, stuck in the fence. even after I pushed the dolphin it was still stuck. It eventually died because it couldn't get air from the surface and made no move to try and breach the water. This is also not happening above water with my sheep and llamas. I hope you can fix and identify this bug.