DISINFECTING 



flows through the pond, increasing 

 the rate of flow is considered the 

 most eft'ective means of controlling 

 this parasite. If fish are held in 

 tanks or aquariums, the addition of 

 hydrochloride or sulfate of quinine 

 to the water at the rate of 1 : 50,000 

 to 1 : 100,000 is recommended. 

 Water containing quinine should be 

 replaced by fresh water when the 

 fish are cured. Recently Schaper- 

 claus (1954) recommended using 

 acriflavine in the same way as qui- 

 nine. Acriflavine is believed to be 

 even more effective than quinine in 

 the treatment of Ichthyophthirius 

 and other external protozoans. 



Copepods. — Suckei-s and min- 

 nows held in sluggish or warm 

 waters may develop raw circular 

 wounds with what appears to be a 

 slender bonelike splint projecting 

 from the center of each lesion. The 

 white splint actually is a copepod 

 parasite, Lernea sp., which has 

 burrowed head first into the flesh, 

 usually beneath the dorsal fin. This 

 parasite is common in southern por- 

 tions of the Lake States and is more 

 abundant southward. 



The projecting i>ortion of the 

 parasite contains reproductive or- 

 gans which scatter eggs into the 

 water as the host fish swims about. 

 These eggs hatch into tiny free- 

 swimming larvae. The larvae, in 

 time, attach themselves to another 

 fish, transform their body shape to 

 a great degree, and burrow in. 

 Meehean was able to cure the infec- 

 tion on fancy goldfish by reducing 

 the pond level to a point wiiere 

 water flowing in and out of the pond 



produced a mild current. The 

 young that hatched did not reinfect 

 the fish, and the adult parasites 

 dropped off after they reproduced. 

 Infected goldfish could be healed in 

 about 10 days. 



Recently a chemical, gammexane, 

 has been recommended for treat- 

 ment of fish infected with the cope- 

 pod Argulus sp. It may also be 

 effective against other copepods. 

 It should be added to water contain- 

 ing infected fish at a rate of 0.1 

 p. p. m. and mixed well. It is rec- 

 ommended that after 2 to 3 days of 

 treatment, the water containing 

 gammexane should be replaced 

 with fresh water. Since this is a 

 new and little-known treatment, it 

 should be carried out with great 

 caution. 



DISINFECTING PONDS AND 

 EQUIPMENT 



The incidence of disease can be 

 greatly diminished or even entirely 

 avoided by observation of certain 

 sanitary measures. Some of them 

 will be listed here. For more detail, 

 see publications by Davis (1947 

 and 1953) and O'Donnell (1947). 



If disease recurs frequently, the 

 hatchery must be carefully exam- 

 ined to determine the source of in- 

 fection. Most frequently the source 

 of infection can be found in not- 

 completely cured fish or in older fish 

 (brood stock), which may serve as 

 a reservoir of infection without any 

 visible symptoms of a disease. 

 Since frequent treatments are costly 

 and time consuming, it is often bet- 



367913 O— 5€ 



61 



