CHAPTER VI. 

 FISH MALADIES. 



HILE according to an old saying 

 'an ounce of prevention is prefer- 

 able to a pound of cure," even with 

 the greatest and best of care, maladies, 

 parasitic or nonparasitic, may appear in the 

 aquarium. If parasitic, they have been 

 caused by the introduction of fishes and 

 plants from infected waters, if nonparasitic, 

 mistakes in feeding, sudden changes in tem- 

 perature or similar happenings may be re- 

 sponsible for their appearance. 



In cases where it is only a question of 

 replacing common and easily obtainable in- 

 mates it is safest and most satisfactory to 

 remove the contents of the aquarium, sub- 

 ject it to a thorough cleaning and restock 

 it with healthy plants and fishes. Where 

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