48 



FBESH-WATEE AQTJABIA. 



prevent their being sucked up, the end of the siphon which is 

 to go in the aquarium should be covered with a piece of mosquito 

 net or similar material. 



The position of an aquarium is an important matter, for very 

 much depends upon the regulation of the light. Light is 

 necessary to the growth of the plants, and to the production 

 of oxygen. But too much light wiU encourage the development 

 of the freshwater Algse commonly called Conferva. This con- 



riG. 38. Method of Emptying an Aquarium. 



ferva is a vegetable growth which appears upon the inside of 

 the glass of the aquarium, depriving it of its transparency. It 

 grows also upon the plants, interfering with their welfare, 

 and it will quickly spread, if unchecked, throughout the 

 water, making it thick, green, and unsightly. Care is there- 

 fore necessary to guard against both too much, and too little 

 light. The latter is much to be preferred to the former. The 

 rays of the sun should never fall directly upon an aquarium, 



