About the control of Ergasilus...
D.L. Mitchum, in his book Parasites of Fishes in Wyoming, gives these
treatments for general copepod and ectoparasite control:
1. Masoten (Dylox): 0.25 to 0.5 ppm 5 times at weekly intervals (kills
adult Argulus and larval Lernaea, but not adult Lernaea)
-see Hoffman and Meyer 1974. Parasites of Freshwater Fishes: A
Review of their Control and Treatment. 224 pp. T.F.H. Publ. Inc,
Neptune City, NJ.
2. Salt (NaCl) in the tanks may give some control (0.2% to 0.5% for 3-5 days)
3. Hydrogen Peroxide (H2O2): 250 to 500 ppm flush or dip for 15 minutes
R.J.G. Lester and F.R. Roubal in Fish Diseases and Disorders (P.T.K. Woo
ed.) give treatments used specifically for Ergasilus. The first 5 are
cited from Kabata, 1985 (Parasites and Diseases of Fish Cultured in the
Tropics. Taylor and Francis, London):
1) copper sulphate and ferric sulphate in a 5:2 ratio
2) Dipterex (Dylox, Chlorophor, Foschlor, Neguvon, Masoten) at 0.15 ppm
for 6 hours
-Hogans (1989. Journal of Fish Diseases 12:529-531) reported successful
treatment of E. labracis on Atlantic salmon with Neguvon at 0.25 mg/L
3) Bromex (dimethyl 1,2-dibromo-2,2-dichloroethyl phosphate): 0.125-0.15
ppm in water of greater than 400 ppm chlorinity (freshwater fish are more
sensitive to the treatment)
4) Malathion: 0.2 ppm for 6 hours
5) the dyes Brilliant Green and Violet K at 0.1 mg/L killed nauplii in
3-24 hours
E. ceylonensis on the Asian cichlid was successfully treated with 3-5 ppm
potassium permanganate.
As always, the specific treatment you use will depend on your resources,
and your pond set up...it would be wise to try any treatment on
individual fish in aquaria before treating the whole pond, just to get an
idea of the effect on the fish themselves.
Derek Zelmer
