454 U. S. BUREAU OF FISHERIES 



cylindrical tanks can be easily equipped for this purpose. The treat- 

 ment may be made even more positive by scrubbing tlie trough or 

 tank every day with a strong salt solution after removing the fish. 

 In warm weather infected fish may be cured by this method in 7 to 

 10 days, and further epidemics can be prevented by quarantining 

 newly brought in stock in this way. Successful treatment in any 

 case depends upon combating the disease when the first symptoms 

 are noticed and continuing it imtil all the parasites have had a 

 chance to drop from the fish. 



Nets and siphons used around infected fish should be sterilized 

 each time thej are used in a strong brine solution, lest the parasites 

 be transferred to other tanks. Detailed information on this disease 

 may be obtained by consulting Bureau of Fisheries Document 

 No.^959. 



It is not possible to enter into details concerning these diseases 

 and their treatment. Further information on the subject may be 

 obtained from the standard books on goldfish culture, a selective 

 list of which is herewith appended. Many of these books may be 

 consulted at the public libraries. 



HOW TO DISTINGUISH SEX 



In goldfish, as well as in other fishes, the male and female are so 

 similar in external appearance that the sex can be determined only 

 by an examination of the internal sexual organs. The following ex- 

 tract from Aquatic Life will be of interest to amateur aquarists : 



Quite the first question to be asked by one desiring to breed goldfish is how 

 the sexes may be distinguished. It has been sliown that a slight difference in 

 contour exists in the region about the anus, but it is exceedingly hard to dis- 

 cern, and not a few experienced fanciers will refuse to guarantee the sex of a 

 fish based on this feature alone. 



When in condition to breed, the distinguishing points are very evident. The 

 male develops tubercles or " salt spots " on the gill plates and along the first 

 ray of the pectoral fins. These marks may be absent from the fins and but few 

 in number on the gill plates. The tubercles are usually considered an infallible 

 distinction, but are not absolutely so. Once in a lifetime a fancier may find a 

 female Avith tubercles. 



The female, except about the anus, exhibits no sexual difference until the 

 development of the roes causes a distention of the body, which is more evident 

 from a top view than from the side. Other than this it possesses no characters 

 to distinguish it from the male. If both sexes are in the same tank, precocious 

 males may " drive " barren females, and in that manner aid in identification, 

 but a doubt may be cast on the certainty of it by the fact that males will 

 sometimes drive other males. 



REARING YOUNG GOLDFISH 



As goldfish sometimes spawn in aquaria, the following advice is 

 given for the benefit of those who may desire to protect the eggs and 

 rear the resulting fry. 



Goldfish begin breeding in their second year, and while thev may 

 continue to reproduce for six or seven years they yield the maximum 

 number of eggs in their third and fourth years. When the male fish 

 begins to follow the female about the aquarium it may be assumed 

 that spawning will occur very soon. The fish may be allowed to 

 remain in the aquarium and the eggs removed later, or they may be 

 transferred to another tank which has been specially prepared \yith 

 suitable aquatic plants to receive the eggs. In stocking the aquarium 



