AILMENTS AND DISEASES 



o 



Fungus on Spawn. The spawn of fishes is attacked by a fungus 

 which manifests itself by short hairliice growths on the surface. Fig. 75. It 



is usually one of the species of the Saproleg- 

 niacese, Saprolegnia ferax or Dictyuchus polyspo- 

 ''""'''■' rus-, the spores of which are present in all natu- 

 ral waters, and are more fully described hereafter. 

 Treatment. There is little to be done 

 for this diseased condition other than to pick 

 out the affected eggs with tweezers. Even then 

 more fertile eggs may be injured than would be 

 saved. Under good conditions only the un- 

 fertile opaque eggs are attacked; and if the 

 parents are healthy and the water conditions 

 good, these are not likely to be present in suffi- 



Fig. 75. Fungus on Spawn. . \ , . i r u 



SaproUgniafera^. cicnt number to Warrant the removal of the 



Greatly enlarged. affccted spawn. If the fishcs are Weak or ovcr- 



spawned, at times nearly all the eggs are unfertile or the fry hatches weak, 

 and on such occasions all the eggs and fry may be attacked by the fungus. 

 When in a day or two the spawn shows a majority of affected eggs, it is 

 best to destroy both it and the spawning plants, to prevent a further 

 spread of the fungus and the diseased condition. 



It is probably always best to take the spawn and the plants to which 

 it adheres from the spawning bed and place them in filtered water to hatch, 

 thus largely avoiding the danger of the presence of fungus spores and 

 those of parasites; but a few pots of growing plants should be introduced 

 to supply the necessary oxygen and to prevent the asphyxiation of the 

 fry. A small dish containing clean soil should also be furnished as it con- 

 tains substances necessary for nutrition and will stimulate the development 

 of minute plant and animal life, the first food of the young fry. The presence 

 of these low forms is manifested by the greenish color of the* water. 

 After the fry are a week old, a half pint of water of pronouncedly green 

 color should be added every few days, and then live food should be fed. 



White Fungus. One of the most frequent diseases of the goldfish 

 and other aquarium fishes is manifested by the appearance of a white coating 

 on the tail and fins which spreads to the body, operculas and into the gills 

 of the fish, destroying the fins, covering the body with a threadlike scum and 

 finally causing the death of the fish from exhaustion, asphyxiation and inter- 

 ference with the proper functions of the skin by obstruction of the surface 

 pores and the induced inflammation. Figure 76. 



The disease is most often introduced into the aquarium by newly ac- 

 quired fishes that may have been shipped long distances in cans containing 



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