long term effect of Formalin

[avandss]

Does anyone know the long term effects of concentrated formalin dips and formalin baths on a fish? i mean this stuff is extremely toxic, it must have some long term effect

also whats the longest lasting fish you have that went through a formalin process?

 

[Reef Frog]

I can't answer your question directly. But I have read that it's "hard" on fish, but to what extent I can't say. I think it's the methanol that is the problem.

The Seachem company has a replacement product called Paraguard that is sold as a "safe replacement" for formalin. I've used it on all of my fish as per label instructions with zero problems on common fish. I have seen a fluke or exo-parasite on occasion in the dipping container (black works best).