322 THE AQUARIUM 



slope it gradually from back to front, and toward one 

 corner. This aids observation, and causes refuse to gather 

 at the lowest point, whence it may easily be removed with a 

 rubber siphon or glass tube. The most desirable aquatic 

 plants derive their nourishment directly from the water, 

 so that the gravel's chief function, as far as the plants are 

 concerned, is simply to hold them in position. Lilies and 

 certain other delicate plants require soil and may be set in 

 small pots, with the soil covered with gravel. 



Small tanks should not be obstructed with rockwork, but 

 if something of the sort is desired, it is best constructed of 

 natural stones, in the form of arches, bridges, etc. Artificial 

 castles, images and other articles of the sort are in decidedly 

 doubtful taste, and will not be used by the discriminating. 



The plants with which the aquarium is to be •stocked have 

 much to do with its ultimate success, and should be selected 

 with the greatest care. The aquarist who lives in the coun- 

 try or suburbs will get much pleasure from collecting them 

 himself from neighboring ponds or streams. Almost any 

 submerged aquatic plant found growing naturally will thrive 

 in the aquarium, and a little experience will quickly demon- 

 strate the few which will not. If the beginner is not so 

 fortunately placed, he must depend on the dealer for his 

 supply. Curiously enough, the plant most commonly kept 

 by dealers is one of the most unsatisfactory in the aquarium. 

 This is Fanwort (Cabomba), of which there are several 

 species. All are difficult to keep healthy except under the 

 best conditions, but if they must be used, the bundles in 

 which they are sold should be separated, and each sprig 

 should have from one-third to one-half of its base removed. 

 Each should then be planted separately. 



The best plants for the amateur are the Swimming Arrow- 

 wort (Sagittaria natans) and the various species of Water- 

 weed (Anacharis or Elodea). The former is somewhat 



