common to the aquarium fanciers of the world. 

 They have not even acquired that funda- 

 mental knowledge necessary to the successful 

 holding of fishes in captivity in healthful con- 

 dition, to say nothing of inducing the exer- 

 cise of the generative instinct. Menagerie 

 methods prevail, and but for constant renewal 

 at great expense, their tanks would be empty. 



SAND, SOIL, GRIT OR PEBBLES? 



Considerable discussion has be^en evoked' 

 at meetings of the Aquarium Society of Phila- 

 delphia, by the important query ''What is the 

 best planting medium in the fresh water 

 aquarium, sand, soil, grit or pebbles?" At 

 first a divergence of opinion was expressed, 

 but later experimentation led to an almost 

 unanimous concurrence in what was since 

 adopted as the best practice. 



Some desirable aquatic plants, sagittaria, 

 Vallisneria, anacharis, cabomba and nitalla, 

 will thrive and exhibit paler green leaves 

 when set directly in the sand; but other 

 plants, ludwigia, potamogeton, moneywort and 

 water-poppy, require soil to continue their 

 growth and to survive under the changed con- 

 ditions. 



The best practice, it has been found, is to 

 place a two to two and one-half inch layer of 

 thoroughly washed bar or beach sand in the 

 aquarium, into which shallow dishes or pots 

 containing clean turf and the last-mentioned 

 plants are arranged, then those to be planted 

 directly in the sand introduced, and the whole 

 surface covered with a one-inch layer of small 

 beach pebbles, known as grit. A few larger 

 pebbles or brookworn stones may be scatter- 

 ed over the surface to produce a natural ef- 

 fect. 



For the marine aquarium mixed sand and 

 grit is preferable, as it offers the best medium 

 in which some of the animals may follow their 

 natural habit of burrowing and hiding. 



Grit permits the finer particles of humus to 

 sift through to the sand layer, to serve as 



63 



