Axolotls get stuck on blocks when swimming

Summary: Axolotls, when put into a pool of water with a bar of blocks running through it, tend to get stuck trying to swim through the bar rather than around it. 

To Reproduce: Construct a pool of water. Place extra blocks into the pool to form a bar. Summon axolotls into the pool.

Expected: Axolotls will swim around, over, or under the blocks. 

Observed: Axolotls swim directly into blocks and keep trying for some time.