158 FISH DISEASES 



from two to five weeks old, and is easily responsible for more losses 

 among goldfishes than all other causes combined. The gills become 

 inflamed and swollen, presenting a distended appearance. Owing to 

 the minuteness of the fish at this period a further observation is dif- 

 ficult except with a magnifying glass, which shows white threads like 

 bristles sticking from the gill plates and openings. The disease is 

 highly contagious, so that if one affected fish is found in a thousand, 

 it is very difficult to save any of them, even though the sick fish be 

 removed at once. 



The other form affects mainly young fishes about 2 inches long. 

 The gills swell rapidly, the infection spreading to the throat and 

 producing a gray or whitish appearance. Without treatment, death 

 is sure to come quickly. This was formerly a common disease among 

 fancy fishes, but for some unknown reason has largely subsided; we 

 hope permanently. 



Treatment of Fry. Innumerable experiments have been tried to 

 cure this devastating disease, but without consistent results. So fatal 

 is it considered by many expert fanciers that when they find a few 

 affected fishes they destroy them, together with perhaps thousands of 

 their fellows in the same tank without attempting a cure, throwing 

 out bad and apparently good alike. The tank is then disinfected with 

 strong salt water or more powerful germicides. The great trouble 

 is that any chemical which will kill the parasites is also very apt to kill 

 the delicate fry. However, it is almost certain a cure can be found, 

 and it is a great pity to neglect an opportunity for experimenting. 

 Cases have been cured, but exact data are lacking. Nevertheless, we 

 have two experimental points to start from. The first and more 

 likely is with permanganate of potash. A well-known and thoroughly 

 reliable breeder claims to have cured over one thousand fry by mak- 

 ing the water a "pale purple" with this chemical, leaving the fish in it. 

 To gauge a permanganate solution by color is most difficult. If one 

 looks through 12 inches of water, the color will be 12 times as deep as 

 through 1 inch. We would suggest trying I/2 grain by weight to the 

 gallon. This just flavors the water. (Tasting without swallowing 

 will do no harm.) If fishes not yet affected are removed from their 

 diseased companions and placed in such a solution for half a day, it 

 is reasonably sure that many, if not all, could be saved, taking care, 

 of course, not to return to an infected tank. Here it might be repeated 

 to advantage that small fry should be lifted with a spoon and trans- 

 ferred carefully, avoiding pouring or any violent movements. 



