Rach, J.J., T. M. Schreier, M.P. Gaikowski and S. M. Schleis.  2003.  Efficacy of formalin to 
control mortality associated with Saprolegniasis infections on channel catfish (Ictalurus 
punctatus)  Submitted to the U.S. Food and Drug Administration Center for Veterinary Medicine. 
 October 22, 2003.  236 pp.

A non-clinical study was conducted at the Upper Midwest Environmental Sciences Center, La 
Crosse, Wisconsin to evaluate the efficacy of formalin to control mortality associated with 
external saprolegniasis infections on channel catfish (Ictaturus punctatus).  In trial 1, formalin 
treatment regimens of 0, 75, or 150 mg/L for 60 min were administered once every-other-day for 
a total of three treatments.  In trial 2, formalin treatment regimens of 0 or 75 mg/L were 
administered for 60-min once daily for a total of seven treatments.  In both trials, each treatment 
regimen was tested in triplicate and each replicate contained 10 fish at test initiation.  In trial 1, 
mean percent survival was 13 % (control), 27 % (75 mg/L), or 63 % (150 mg/L).  Survival was 
significantly greater (P ? 0.01) in fish treated with 150 mg/L formalin compared to the control 
group.  In trial 2, mean percent survival was 3 % (control) and 33 % (75 mg/L).  Survival was 
significantly greater (P ? 0.01) for fish treated with 75 mg/L formalin compared to the control 
group.  All fish that died during the study were infected with fungus.