its hard for the body to expel the cyanide once it binds with the enzyme in the mitochondria.... unless it is a minimal dosage... which i doubt so... the fish will eventually die due to lack of the ability to use oxygen... as the organ most likely to be affected first is the brain or the heart as they need the most oxygen, chances of survival is low.
In humans the only way to save ppl is to use IV lines and pump chemicals into the blood... we can't do this in fishes as the blood vessels are so thin... so i can conclude that there is practically no way we can save the fishes using the technology at present.