Argulus americanus WILSON 1902 was found on the bowfin, Amia calva, imported from Wisconsin, U. S. A. Eggs laid in a plastic container hatched in 35-37 days at 15°-16°C. Hatched larvae were experimentally infected to a cichlid, Tilapia mossambica. The larvae kept at 23°-26°C grew from 0.6-0.7 mm in total length on Day 0, to 2.5-3.5 mm on Day 20, to 4.5-5.8 mm on Day 40, and a single female larva grew to 6.9 mm on Day 70. Females laid eggs on Day 49 and Day 53. Male specimens on Day 7 and Day 26 are illustrated.