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/(30L0GICAL SOCIETY BULLETIN 



ROUND GLASS AQUARIA. 



being absolutely water-tight, while they re- 

 main in sound condition, whereas the joints of 

 metal-framed aquaria may leak. 



Globes are worthless. Good results can not 

 be expected with them. The restricted surface 

 of a globe at the top lessens the amount of 

 water surface exposed to the air. The more 

 surface exposed for the absorption of air, the 

 better. 



The aquarium should be placed where the 

 amount of light reaching it can be well con- 

 trolled. A north window is best, an east win- 

 dow will do, but e.xposure in other directions 

 will make its care more difficult. If large, the 

 aquarium should be located before it is filled 

 with water. 



Sunlight should not often be allowed to fall 

 directly on it, as it stimulates the growth of 

 algae, and is liable to overheat the water, the 

 temperature of which should be kept steady, 

 not rising above 70 degrees or falling below 40 

 degrees. A temperature of 50 degrees to 60 

 degrees is best, and it should not be allowed to 

 vary. Wami water holds less air than cold 

 water, so that a high temperature is more to be 

 guarded against than a low one. 



Water plants are necessary in the aquarium 

 for the aeration of the water, since under 

 proper conditions of light and temperature 

 they give off oxygen which animals require, 

 while the latter exhale carbonic acid gas. A 

 balance between the animal and plant life of 

 the aquarium is essential for success. Too 

 much plant growth can be checked by reducing 

 the amount of light, which may be shut off by 

 the use of a screen or shade. A greenish film 

 of algae or confervse will at times develop rap- 



idly on the glass and obscure the contents of 

 the aquarium. It will have to be rubbed off 

 occasionally, but it is just as well to let it grow 

 on the side next the window where it will serve 

 to restrict the light and also aerate the water. 

 The growth of algje is lessened by placing the 

 aquarium in a more shaded position. Snails eat 

 algje rapidly and should be introduced for that 

 purpose, and also because their eggs serve as 

 food for small fishes. 



.\llow the aquarium to absorb air from its 

 plant life and from the surface of the water 

 for a day or two before putting in the fishes. 

 The latter should be few in number at first. 

 Snails may be added later. Dealers in aqua- 

 rium supplies usually keep plants, snails, tad- 

 poles, newts, and other small creatures as well 

 as fishes. 



With running water, plant life can be dis- 

 pensed with. A collection of large goldfishes 

 in the New York Aquarium has been kept in 

 good condition for many years in flowing Cro- 

 ton water, standing its low temperature in 

 winter very well. The fish are, however, 

 much more active in summer and feed more 

 freely. 



The following named water plants are those 

 most frequently used by aquariists ; milfoil 

 [Myriophyllum), hornwort (Ccratophyllum), 

 fan wort (Caboinba), water- weed (Anacharis), 

 tape-grass (Vallisneria), arrow-head (Sagtt- 

 taria) and pondweed (Potainogcton). 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 se- 

 curely. 



