56 



taken from suckers. The adult stage lives in the 

 intestines of water birds.. 



Minnows and suckers reared in ponds or taken from 

 shallow waters along lake shores may be infested. The 

 parasite is known to be of wide occurrence in the Great 

 Lakes and adjoining areas. Because the parasite eggs 

 are spread by water birds and early larval forms live 

 within natural food organisms of fish, there is little 

 chance for permanent control although drying and freez- 

 ing of pond bottoms may reduce chances of infestation. 



Lernaea sp. — Suckers and minnows held in sluggish 

 or warm waters may develop what,appear to be raw circular 

 wounds with a slender bonelike splint projecting from 

 the center of each lesion. The white splint actually 

 is a copepod parasite which has burrowed headfirst 

 into the flesh, usually beneath the dorsal fin. This 

 parasite is common in southern portions of the Lake 

 States and is more abundant southward. 



The projecting portion of the parasite contains 

 reproductive organs which scatter eggs into the water 

 as the host fish swims about. These eggs hatch into 

 tiny free-swimming larvae which, in time, attach 

 themselves to the exterior of another fish, transform 

 their body-shape to a great degree, and burrow in. 



Meehean was able to cure the infection on fancy 

 goldfish by reducing the pond level to a point where 

 water flowing into and out of the pond produced a mild 

 current. The young which hatched did not reinfect the 

 fish, and the adult parasites dropped off after they 

 reproduced. Infected goldfish could be healed in 

 about 10 days. 



There are a number of ways to treat fish diseases. 

 Fish (1938) gives a good description of the best methods 

 for the treatment of trout. His description is pre- 

 sented here: 



Methods of treatment 



Regardless of the concentration of disinfectants used,, the 

 technique of application influences the success of any treatment 

 to no small degree. It might, therefore, be advantageous to 

 briefly outline the various methods of treatment in common use 

 and the recommended technique for their application. 



Aside from medicines administered with the food, treatments 

 may be roughly divided into four basic methods: (1) salting; 

 (2) flushing; (3) hand dipping; and (4) prolonged treatments. 



