THE FRESH-WATER AQUARIUM. 



13 



CHAPTER III. 

 THE FRESH-WATER AQUARIUM. 



tHE first thing to consider after getting the water 

 into our aquarium, and having ascertained that it 

 is free from leakages, is the stocking it with plants. 

 The most valuable kind of vegetation we can have in the 

 tank is the microscopic algae. We cannot obtain this at 

 once, but must wait a little time for its development on 

 the stones and walls of the tank, from the spores floating 

 in the pond or river-water we have introduced. It will 

 first appear as a slight green scum on the surfaces of 

 things, and when well developed will present a beauti- 

 fully jewelled appearance as the delicate filaments be- 

 come beaded with tiny bubbles of pure oxygen which 

 glisten like little diamonds. Hosts of tiny creatures 

 (described further on) will make this algae their home, 

 and these in turn will form a food supply for the larger 

 animals. The larger plants may be planted in the 

 gravel, covering sufficient of the stalk to prevent the 

 plant floating on the surface. For this purpose, young 

 healthy plants should be selected. Of the species 

 most suitable for the aquarium we may select one or 

 more of the following : — The American Pondweed 

 {Anacharis alsinastrum), the Water Starwort {CallitricJic 

 vernd)^ the Pondweeds {Potamogeton natans^ P. densiis, 

 P. crispiis, 6'<:.),the Water Crowfoot {Rmninaihis aqiiatilis), 

 the Frogbit {Hydrocharis viorsus ranee). 



