APPENDIX A 



CARE OF SMALL AQUARIA 



The keeping of small aquaria is now practiced so extensively and 

 there are so many books available on their management that little 

 more need be considered here than the principles involved. Aquaria 

 suitable for the biological laboratory or the home are available in 

 cities everywhere. Dealers can supply them in so many forms and 

 sizes that it is unnecessary to describe their construction. In most 

 ])ublic aquariums table space is provided somewhere for the keeping 

 of aquatic animals of small size that do not require flowing water. 

 The aquaria used for such exhibits are provided with aquatic plants, 

 which serve to aerate the water. Success with them is dependent 

 upon a proper balance between the animal and plant life they 

 contain. 



An aquarium holding 8 or 10 gallons of water will be easier to 

 maintain in good condition than one of small size and will care for 

 a larger number of fishes with a greater degree of safety. An 

 aquarium of rectangular shape is best for permanent use. It should 

 be of strong, clear glass — preferably plate glass — set in a metal 

 framework, and have a slate bottom. 



Aquaria of rectangular form made wholly of glass can be pur- 

 chased and are cheaper, but the glass is never quite clear, and they 

 crack more readily from changes in temperature. Cylindrical glass 

 aquaria are still cheaper, but they distort the forms of the objects 

 they contain to some extent and are also liable to crack. However, 

 aquaria made wholly of glass have the advantage of being abso- 

 lutely water-tight while they remain in sound condition, whereas 

 metal-framed aquaria may develop leaks. 



Globes are unsatisfactory. Good results can not be expected with 

 them. The small opening of a globe permits too small an amount 

 of water surface to be 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 reach- 

 ing it can be controlled. Sunlight should not be allowed to fall 

 directly on it except for an hour or two a day in the winter, as it 

 stimulates the growth of algse and may overheat the water, the 

 temperature of which should be kept steady, not rising above 75° 

 or falling below 45°. A temperature of 50 to 60° is best, and it 

 should not be allowed to vary. Warm 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, as under proper conditions of light and temperature they give 

 off oxygen, which animals require, while the latter exhale carbonic 



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