Axolotls attacking Pufferfish does not cause the Pufferfish to puff

When an axolotl attacks a pufferfish, I'd imagine the pufferfish should puff up and defend itself, as when a player approaches it. But the pufferfish does not do this when an axolotl approaches. If it is uninflated when an axolotl attacks it, it just stays uninflated and is promptly killed by the axolotl in two hits, instead of puffing up to defend against the attack.