A NEW METHOD OF COMBATING FUNGUS ON FISHES 



IN CAPTIVITY. 



By PAUL ZIRZOW. 

 [Translated from the German.] 



Several methods have already been proposed and used for combating 

 parasites attacking fishes and for the treatment of diseased fishes. These 

 methods consist in the application of baths of dilute watery solutions of 

 substances which act as death-dealing agents on the micro-organisms. Greatly 

 diluted solutions of salicyl and ammonia have been used for such baths. The 

 use of ammonia (i : looo) for this purpose, proposed by Doctor Roth, of Zurich, 

 proved more effective than salicyl, according to experiments made at the 

 biological station of Munich, as this agent entirely kills off parasitic worms. 



The treatment of fishes with baths of this kind has, however, the disad- 

 vantage that the fishes themselves suffer from the effects, so that the treatment 

 can be given only with the greatest precaution and during a short period. In 

 order to obtain a complete recovery, repeated baths have been recommended. 

 The treatment of fishes, especially those attacked by fungus diseases, is 

 necessarily very tedious, since the destruction of fungus growth can not be 

 attained so quickly as the extermination of parasitic worms. 



This disadvantage in the length of time required for effectual treatment 

 with baths, as well as the injurious effect upon the diseased fish, may be over- 

 come by a method which has been used hitherto only in the transportation of 

 live fish. The feasibility of this method has been shown by the results of 

 several experiments. 



The new method of combating fungus diseases consists in keeping the dis- 

 eased fishes in water regenerated by ozone until the disease has disappeared. 

 The adequacy of such treatment was demonstrated by an experiment which 

 took place in Galatz in October, 1906, during test of a method of keeping fish 

 alive by means of water regenerated with ozone. 



This experiment, in which tench, carp, and shad were used, showed that 

 injured fishes which had fungus filaments and growths on their wounds when 



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