Fishy treats?

[John]

I do know that fish and frog/rep water dechlorinators are not cross compatible, so maybe the fish de-chlor is bad for them?

I'm a professional research chemist and my main research interest is in water chemistry and biologically relevant pollutants. I don't know of a dechlorinator product sold for fish or amphibians in the US or Europe that is not compatible with both groups of animals.

However, amphibians are sensitive to many fish medications (dechlorinator products are not a medication, despite what the label might say) and in some cases what does not harm fish can be quite poisonous to amphibians. That is probably where that information originated.