Acute toxicity tests of formalin have been conducted for freshwater fish by several
investigators indicating that
formalin has a relatively low toxicity for freshwater fish However,reliable data are lacking for saltwater organisms The 72-h formalin LC50 for the bullseye puffer fish indicated that this tropical species tolerates similar concentrations than those
reported for Anguilla americana , but higher than the reported for Atlantic salmon fingerlings On the other hand, the striped bass fingerlings,Morone saxatilis, has been reported with considerable lower tolerance to formalin However, these authors found that striped
bass increased tolerance to formalin as salinity approached 10– 13x