Tiger Shark Health declining too fast to stay alive

[Witchy]

I put the Tiger Shark in a tank with everything it wants, surplus filtering, it's very happy. Except it's health is dropping so fast. Like on med speed it takes just seconds to go from full to almost dead.
When a Marine expert is in the tank it refills but by the time they've done the transition animation to leave the tank it's already below half.
Testing with two sharks, same issue.

[Witchy]

Have got my own solution per the discord.
Zappers will kill other fish they're in a tank with. (this is not at all clear on the card for the fish)