A comparison of tolerance of fingerling black crappie, white crappie and largemouth bass to Fintrol-5 was conducted in aquaria. White crappie were found to be more susceptible to Fintrol-5 than were black crappie and largemouth bass. Largemouth bass and black crappie showed similar tolerance to the toxicant. The mortality of largemouth bass and black crappie was significantly reduced at a pH of 8.0-8.5. All three species suffered significant mortalities beginning with .04 ppm Fintrol-5 at a pH of 7.0. One ppm KMn04 significantly reduced mortality by detoxifying Fintrol-5.