THE PUBLIC AQUARIUM 



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fanwort {Cdhomha), water weed (Anacharis), tape grass (Vallis- 

 neria), arrowhead {/Sagittaria) , and pondweed {Potamogeton). 

 Many other species will serve the purpose. Plants may be anchored 

 by pressing them down into the sand or gravel. Thin strips of lead 

 wound loosely about their roots will hold them securely. 



In a well-balanced aquarium the water should not be changed at 

 all. In fact, it is better without any addition other than that 

 required to replace what is lost by evaporation. Water should not 

 be added until it has been kept in the same room with the aquarium 

 long enough to acquire the same temperature. 



