REARING THE YOUNG FRY. 205 



is well known, a corresponding disease among higher 

 orders, called fatty degeneration of the heart. Dr. 

 Slack of the Troutdale Ponds speaks of this disease 

 among trout, and says that a constant diet of curd will 

 produce it. 



1 8. Spotted rash. I once gave an abundance of 

 water-cresses {Nasturtium officinale) to a lot of young 

 fry that had been kept wholly without vegetable food. 

 In forty-eight hours their bodies were covered with 

 brown spots, and within the next forty-eight hours 

 most of the fish died. I cannot say for a certainty 

 whether it was a rash coming from within, or a parasite 

 coming from without. I have called it spotted rash 

 for want of a better name, and have noted it for future 

 observers. Whatever it is, it is certainly very fatal. 



19. Strangulation by food. Trout of all ages will 

 sometimes take too large pieces of food, which they 

 cannot disgorge, and which they cannot swallow, and 

 therefore get choked to death. You will see them 

 in the pond with their eyes protruding, and head 

 very much swollen laterally, and the offending morsel 

 sometimes projecting from the mouth. The situation 

 is usually fatal, but not always ; they will sometimes 

 recover, after having had a frightfully swollen head and 

 eyes ; sometimes you can save them by pulling the 

 piece of food out of their throats. 



20. Cannibalism, nibbling. This is a frequent cause 

 of death among the young fry. Trout are cannibals ; 

 they will always eat each other, if they can, when they 

 are hungry ; and this can be taken as a rule, that a trout 

 of any size, if hungry enough, will eat a trout of half its 



