MYXOSPORIDIASIS : PREVENTION 259 



of insects, minute Crustacea, etc., that form a con- 

 siderable proportion of the food of fishes, apart from 

 the harm to the fish themselves, is incommensurate 

 with the amount of success achieved in combating 

 the disease. The remedy is often worse than the 

 complaint when the utility side is considered. 



Finally, the use of tonics in water has been sug- 

 gested, some form of iron salt being the most 

 favoured. While undoubtedly iron salts are tonics, 

 and of use in combating anaemia, it is almost im- 

 possible to utilize them on a large scale. Water 

 currents, decomposition due to other chemicals, dis- 

 like of medicated waters by the fish themselves, all 

 tend to defeat such attempts at curative methods, 

 and force the conclusion that, here as elsewhere, the 

 health of the fish population is to be maintained by 

 strict attention to preventive measures, rather than to 

 treatment'once the disease has manifested itself. 



