154 FISH DISEASES 



make no inroads on a fish in good condition. A weakened fish once 

 infected will breed so many bacteria that they can successfully attack 

 the remaining well fish. White fungus, therefore, is contagious, and 

 the suft'erer should be removed from its fellows at once. This dis- 

 ease is caused by overcrowding, overfeeding, lack of proper plant life, 

 sudden temperature changes and by bruises in shipment. 



Treatment. Fishes suffering from white fungus should be treated 

 exactl}- the same as those having fin congestion. If the fins have 

 become very much frayed and it is necessary to trim them, this can 

 best be done by a sharp knife, using a board to cut on. Scissors make 

 a very poor result. It is well to treat the new cut edges with a per- 

 manganate solution of one grain to a glass of water. By grain we of 

 course always mean a certain quantity of weight, and not simply a 

 small particle. 



Sometimes raw spots are left after the fungus has been removed. 

 These or similar spots from other causes can be greatly helped by the 

 following method : Wrap the head and gills of the fish in a moist rag, 

 dry the aft'ected spot and apply some Turlington's Balsam with a 

 small piece of absorbent cotton. Allow to dry for three or four min- 

 utes. This will not endanger the life of the fish so long as the gills 

 are kept moist. 



Black Fungus. Many have supposed this disease to be invariably 

 fatal, but this is not the case. If taken in time, the majority of cases 

 can be cured. The great trouble is that the fish is in a run-down 

 condition before contracting the disease and has little power to with- 

 stand the necessarily severe treatment. This disease manifests itself 

 more on the body than the fins, at first presenting a dark gray appear- 

 ance, later turning black and peeling oft, leaving raw spots. A com- 

 mon place for the first appearance is the center of the gill plates, and 

 also on the sides of the fish where they would be most likely to rub, 

 for the parasites are conveyed principally by contact. The protozoans 

 causing this serious complaint are animal parasites which soon lodge 

 themselves so deeply in the skin of the fish as to make treatment dif- 

 ficult. If they get into the gills the case is considered hopeless. 



Tre.\tment. Start at once on the increasing salt method 

 described on page 151, only carrying it further. Over a period of from 

 three to four days the strength of solution should be carried to two and 

 one-half ounces to the gallon. Goldfishes can stand a great deal of 

 salt if brought to it gradually. (The same is true of most other 

 aquarium fishes.) As before noted, the strength should be slowly 

 reduced before returning to normal water. After the maximum 

 strength of solution is reached the fish should be pencilled on the 



