Fish Maladies 335 



pests, true parasites, weaken the fish, its ap- 

 pearance changes, the gills look inflamed 

 and even the scales seem to change their 

 shape and color, while all the fins contract 

 and appear to stick together. After consid- 

 erable suffering the fish becomes slow and 

 heavy in its motions and finally dies of ex- 

 haustion. 



Still smaller organisms of the class Pro- 

 tozoa and designated as Ichtyophthirice 

 (Fish Destroyer) may attack our aquarium 

 fishes regardless of species or value. They 

 do not live on the surface, but inside the 

 epidermis of the fish. Once there, they in- 

 crease at a tremendous rate and cause the 

 formation of small white pustules, at first 

 sporadic, but as the disease progresses, in- 

 creasing in such numbers that they cover 

 the whole fish, fins, eyes and nose included, 

 with irregular white blotches. A heavy 

 coating of sticky slime then envelops the 

 fish and the epidermis commences to drop off 

 in flakes. Often the substance forming the 



