284 THE AQUARIUM AND WATER PLANTS. 



As we have before said, the great element of success is 

 proportioning the quantity of animal and vegetable life. 



The usual rule is, two fish to every gallon of water, 

 with snails to eat up any slime or refuse. If well 

 managed, the water need never be changed. To attain 

 this, you must use only healthy plants, and not too 

 many of them, and have the bottom of clean pebbles 

 and sand. 



If the water evaporates, it must of course be re- 

 newed, and should it become stagnant, it may be aerated 

 by turning portions of it from one vessel to another. 

 Of course if decay of the plants takes place, or animals 

 die in the water, the only remedy is to empty, thoroughly 

 cleanse all, and begin anew. 



The Wardian case and aquarium may often be very 

 prettily combined by raising rock-work in the water, 

 planting ferns, and other moisture-loving plants upon it, 

 and covering the whole with glass. 



Where access to water can be easily had, a fountain 

 in the centre might be contrived, and the effect would 

 be most beautiful. There is, however, a water plant 

 which will thrive very well in the parlor, and require 

 but little care. 



