Submitted to: Book of Abstracts Aquaculture America
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 2007
Publication Date: February 10, 2008
Citation: Mitchell, A.J., Darwish, A.M., Fuller, S.A. 2008. Comparison of tank treatments of copper sulfate and potassium permanganate on sunshine bass infested with ichthyobodosis (costiosis) [abstract]. Book of Abstracts Aquaculture America. p. 246. Technical Abstract: Ichthyobodo necator, more commonly known as Costia, causes large losses among fish populations, particularly those cultured in tanks. Ichthyobodosis usually occurs in groups of crowded fish that have been poorly fed and held in waters with low flow, but its occurrence is not limited to these conditions. A number of treatments, including acetic acid, formalin, salt, potassium permanganate (KM), and copper sulfate (CS), have been used for years against this parasite, but most of the evidence for the effectiveness of these treatments is anecdotal. Our study was set up to evaluate the effectiveness of KM and CS against a heavy, naturally-occurring Costia infestation on sunshine bass held in tanks. A preliminary examination of 10 fish revealed that every fish had ichthyobodosis and 90% were heavily infested (in either the microscopic preparation of gill tissue or the skin scrapings, 60+ organisms were counted in 60 sec). Twenty-three fish (3.1 g average weight) were randomly placed in each of 12 tanks supplied with aeration and 10 L of flow through water (about 200 mL/min). Within an hour of stocking the fish, 4-h static treatments of 3 mg/L KM and 2 mg/L CS were applied to 4 tanks each. Four tanks remained as positive controls (PC). The same treatments were applied 2 d later. The total alkalinity and total hardness of the water used in the study was 206.6 and 95.0 mg/L, respectively and the water temperatures during the study ranged from 24.8° to 25.3°C. Mortalities were recorded daily. Two d after the application of the second treatments, parasite infestation levels were accessed by making 60 sec counts of Costia from both the gills and skin scrapings of five surviving fish from each tank. An infection rating was determined from an average of the counts made in 60 sec from both the gills and skin scraping for each fish. The infection ratings was 0 = no Costia found; 1 = 1 to 19; 2 = 20 to 59; and 3 = 60 or more. From the 5th to 7th d, parasite assessments were made from moribund and freshly dead fish to verify if Costia at least was contributing to the mortality. The CU, KM and PC treatments resulted in significantly different average survivals by d 7; these were 88.9%, 20.4%, and 0%, respectively. Two day after the second treatment, fish subjected to the CS, KM and PC treatments had an average infection rating of 0, 2.1, and 2.97, respectively. All moribund and recently dead fish examined d 5-7 were heavily infested with Costia, except for one fish from the CS treated group that was extremely malnourished. The two 4-h static treatments of CS at 2 mg/L appeared to be very effective.