Diamond shield and Thunderbolt or eventual death to poisoning.
I think its a bad idea but surprisingly people have been ignorant to it all.
I really like the 3 attack buff. I may regret that when eldinis starts kicking my tail, but it is a needed buff for both the card and water in general. If the card becomes too rampant, which i doubt it will, nerfing its hp to 4 or even 3, may become a good idea.
The whole point of buffing is to make underused cards more usable. No one ever uses pufferfish, it's old version was grossly underpowered compared to Physalia since most shields shut it down. I've NEVER played against anyone other than eldinis, scorpio, etc. that use the pufferfish and I never fear it when they do play it. That sounds like a prime candidate for a buff. Especially since purify recently became better.
I like the fact that several new changes make diamond shield the preferred option. This change as a secondard effect, gives a small 'buff' to diamond shield in that it is actually nedded over permafrost in some situations.