Control of parasitic infestations in killifish (Fundulus parvipinnis)

California killifish (Fundulus parvipinnis) trapped in a Southern California estuary were infested with Gyrodactylus sp, Argulus sp, or Ergasilus sieboldii. They were treated with 0,0-dimethyl 2,2,2-trichloro-1-hydroxyethylphosphonate (DTHP). The effective dosage regimen for Gyrodactylus was 7.50 mg/l for 1 hour on day 1, 3.25 mg/l for 1 hour on day 5, and 0.75 mg/l for 1 hour on day 9; for Argulus, 2.50 mg/l for 1 hour once only; for Ergasilus, 2.50 mg/l for 1 hour once every third day for three treatments. Toxicity testing indicated that repetitive doses of 4.20 mg/l were toxic and that static exposures of more than 1 hour to doses of 7.50 mg/l were lethal to Fundulus.