282 FISH HATCHERY MANAGEMENT 



external bacterial infections of fish and as a prophylaxis in hauling tanks, 

 but results are not dependable. It is available either as acriflavine neutral 

 or as a hydrochloride salt and is considered lOO'/^i active. Generally, it is 

 used at 3-5 parts per million (0.11-0.19 gram per 10 gallons; 0.85-1.4 

 grams per 10 cubic feet) in hauling tanks and at 5-10 parts per million 

 (0.19-0.38 gram per 10 gallons; 1.4-2.8 grams per 10 cubic feet) in holding 

 tanks. 



Cost prohibits the use of acriflavine in large volumes of water, such as 

 ponds. 



CALCIUM HYDROXIDE 



Calcium hydroxide (slaked lime or hydrated lime) is registered by the 

 Food and Drug Administration. It is used as a disinfectant in ponds that 

 have been drained. Although calcium oxide (quicklime) probably is better, 

 it is more dangerous to handle and less readily available. Calcium hydrox- 

 ide is used at the rate of 1,000-2,500 pounds per acre (0.02-0.06 pound or 

 10-26 grams per square foot) spread over the pond bottom. 



lODOPHORES 



lodophores are not registered by the Food and Drug Administration. Beta- 

 dine and Wescodyne, non-selective germicides, are iodophores that success- 

 fully disinfect fish eggs. lodophores are much more effective for this than 

 other disinfectants such as acriflavin and merthiolate. Green or eyed eggs 

 usually are disinfected in a net dipped into a large tub or a shallow trough 

 with no inflowing water. After 10 minutes, the eggs should be removed and 

 promptly rinsed in fresh water. For a more extensive description of the use 

 of iodophores, see Chapter 3. 



DI-7V^BUTYL TIN OXIDE 



Di-ra-butyl tin oxide (di-n- butyl tin laureate) is not registered by the Food 

 and Drug Administration. It is effective against adult tapeworms in the lu- 

 men of the intestinal tract, and should be equally so against nematodes and 

 spiny-headed worms, when given orally at the rate of 114 milligrams per 

 pound of fish or fed for 5 days at 0.3"/!i of food (0.3 pound per 100 pounds 

 of food). 



MASOTEN® 



Masoten (Dylox) is registered by the Food and Drug Administration, and 

 can be obtained in a variety of formulations; most common is the 80% 

 wettable powder (W.P.). It is used as an indefinite pond treatment to con- 

 trol ectoparasites such as monogenetic trematodes, anchor parasites, fish 



