232 



AQUARIUM APPLIAXCES 



of cheesecloth suspended in the aquarium. The illustration will 

 show how this may be done. The four corners should be weighted 

 down with bits of lead or stone sewed in. The plants and spawning 

 fish are simpl_v transferred into the net. Confined in this compara- 



^ 



Fig. 219. Sp.wvxing Net 



ti\ely small space, the chances of the eggs becoming fertilized are 

 increased, while the netting is sufficiently open to allow the aquarium 

 \^■ater to flow slowly through it and prevent suft'ocation. In this way 

 the large amount of dirt usually stirred up in an aquarium at spawn- 

 ing time, and which can do the adhesive eggs no good, is entirely 

 a"\'oided. The size of the net will depend somewhat on the propor- 

 tions of the aquarium, but the capacity of net (portion in water) 

 should be about twelve to eighteen inches long, ten inches wide, and 

 ten inches deep. In constructing, allow extra material for space 

 between top frame and surface of water. 



Constant Aquarium Filter. This device is for use in connection 

 ^\-ith the air pump referred to on page 2?i^. It is capable of a num- 

 ber of ^■ariations, once the principle is understood. There are two 

 columns of water in the tubes, one solid and one punctuated hv air 

 bubbles, thereby making it the lighter. This causes it to rise and 

 therefore establish circulation as long as air is supplied. A 3-g-inch 

 diameter glass surgical drain is shown at A. This should contain 

 about eight small openings and be suspended two inches above the 



