AQUARIUM 19 



creatures must breathe that or come to the surface for their 

 supply. How does Mother Nature manage the ventilation 

 of her aquaria, the ponds and streams ? The plants fur- 

 nish part of the air, as we have seen. The open pond, 

 whose surface is ruffled by every passing breeze, is con- 

 stantly being provided with fresh air. A tadpole or a fish 

 can no more live in a long-necked bottle than a boy can 

 live in a chimney. (3) The temperature should be kept 

 between 40 and 50 Fahr. Both nature and experience 

 teach us this. A shady corner is a better place for the 

 Aquarium than a sunny window on a warm day. (4) It is 

 well to choose such animals for the Aquarium as are 

 adapted to life in still water. Unless one has an arrange- 

 ment of water pipes to supply a constant flow of water 

 through the Aquarium, it is best not to try to keep creatures 

 that we find in swift streams. Practical experience shows 

 that there are certain dangers to guard against. Perhaps 

 the most serious results come from overstocking. It is 

 better to have too few plants or animals than too many of 

 either. A great deal of light, especially bright sunlight, is 

 not good for the Aquarium. A pond that is not shaded 

 soon becomes green with a thick growth of slime, or alga3. 

 This does not look well in an Aquarium, and is apt to take 

 up so much of the plant-food that the other plants are 

 starved out. The plants in the school-room window will 

 shade the Aquarium nicely, just as the trees and shrubs on 

 its banks shade the pond. If we find this slime forming 

 on the light side of our miniature pond we put it in a darker 

 place, shade it heavily so that the light comes in from the 

 top only, and put in a few more snails. These will make 

 quick work of the green slime, for they are fond of it, if we 

 are not." 



The aquatic plants of the neighborhood may be kept in 

 the Aquarium, such things as myriophyllums, charas, eel- 

 grass, duckmeats or lemnas, cabomba or fish grass, arrow- 

 leafs or sagittaria, and the like; also the parrot's feather, 



