328 Fresh Water Aquarium 



NONPARASITIC MALADIES. 



A frequent cause of the suffering and loss 

 of our fishes is lack of oxygen in the water. 

 As this gas is as necessary to the fishes as 

 it is to all other living beings, its absence 

 or exhaustion will result in the suffocation 

 of the population of the aquarium. The 

 lack of oxygen may be caused by overstock- 

 ing. If the number of fishes is too large 

 in proportion to the amount of water in the 

 aquarium, the amount of oxygen naturally 

 suspended in the water or exhaled by the 

 aquatic plants will be found insufficient for 

 the need of the fishes, which will come to 

 the surface and try to take from the atmos- 

 phere the supply which the water should 

 give them. Prompt help will usually rem- 

 edy the evil. Part of the fishes should 

 be placed in another vessel, the water should 

 be renewed, some oxygenating aquatics 

 should be placed in the aquarium and no 

 further trouble will be experienced. Quite 



