Moray eels are known to prey on lionfish in the wild. They sneak up on them while sleeping and swoallow them head first, so they can't erect their spines. Lionfish can only deliver toxin if their spines are erected. IMO
, a trigger may nip on the fins of the lion, puffers are known to do the same thing in the ocean. Funniest thing I saw on the discovery channel was a nature thing where they showed lots of huge lionfish being hounded and harrassed by small puffers. The puffers were tearing them up, the lion would swallow a puffer and immediately spit it out. A puffers skin is toxic. There was nothing the lion could do, lions aren't the most agile fish and striking with the spines is awkward, so they couldn't even fight back.