EFFECT OF SPECIES, LIFE STAGE, AND WATER TEMPERATURE ON THE TOXICITY OF HYDROGEN-PEROXIDE TO FISH

Hydrogen peroxide is a drug of low regulatory priority status that is effective in treating fish and fish eggs infected by fungi. However, o nly limited information is available to guide fish culturists in admin istering hydrogen peroxide to diseased fish. Laboratory tests were con ducted to determine (1) the sensitivity of brown trout Salmo trutta, l ake trout Salvelinus namaycush, fathead minnow Pimephales promelas, wa lleye Stizostedion vitreum, channel catfish Ictalurus punctatus, and b luegill Lepomis, machrochirus to hydrogen peroxide treatments; (2) the sensitivity of various life stages of rainbow trout Oncorhynchus myki ss to hydrogen peroxide treatments; and (3) the effect of water temper ature on the acute toxicity of hydrogen peroxide to three fish species . Fish were exposed to hydrogen peroxide concentrations ranging from 1 00 to 5,000 mu L/L (ppm) for 15-min or 45-min treatments every other d ay for four consecutive treatments to determine the sensitivity of var ious species and life stages of fish. Except for walleye, most species of fish tested (less than or equal to 2 g) tolerated hydrogen peroxid e of 1,000 mu L/L or greater. Walleyes were sensitive to hydrogen pero xide concentrations as low as 100 mu L/L. A correlation was found betw een the toxicity of hydrogen peroxide and the life stages of rainbow t rout; larger fish were more sensitive. Generally, the toxicity of hydr ogen peroxide increased for all species as water temperature increased . The results of these experiments demonstrate that it is important to consider the effects of species, life stage, and water temperature wh en conducting hydrogen peroxide treatments.