FISH FOOD 77 



suited to the fish large enough to easily swallow it. As a food for putting 

 growth on fish an inch long or over it probably has no equal. The main 

 drawback to these larvae is that those not eaten quickly by the fish are 

 liable to turn to mosquitoes. This difficulty can be minimized by proper 

 management. Keep the stock of larvae in a tank covered by a sheet of 

 glass, leaving about two inches at one end not covered. Over this open 

 space place a piece of mosquito netting, drawing it up several inches over 

 the opening into a sort of inverted bag. Then draw a string around top 

 edge of tank to secure netting. As the mosquitoes hatch they will fly 

 upward into the netting bag, where they may be killed before lifting 

 the lid to get larvae for the fish. The author usually keeps these larvae 

 in a 5-gallon drinking water bottle, half filled, and with a bit of netting 

 over the top, secured by a rubber band. To get larvae, remove netting, 

 place hand over opening and quickly invert bottle. The larvae in their 

 excitement swim downwards into neck of bottle. Release hand and 

 empty the required quantity. Return bottle to upright position, replace 

 netting and add water to make up to former level. When most of the 

 larvae have been used and a number of mosquitoes remain in the bottle, 

 fill with water (through the netting) and they will be drowned. A 

 netting bag trap secured on neck of bottle will also catch the majority 

 of the mosquitoes. 



The larvae should be kept out of the sun and in as cool a situation 

 as possible so as to retard the hatching. They will stand great crowding, 

 their only requirement being that there is room for them all to get to 

 the surface at one time, for they breathe air. This is one advantage 

 in placing larvae with fish, for, unlike daphnia, they extract no oxygen 

 from the water. By feeding them to the fish we not only do well for 

 the fish, but serve the interests of humanity by cutting down the mosquito 

 pest. In open pools goldfishes are one of the best agents in keeping the 

 neighborhood free of mosquitoes. Unfortunately the mosquito larvae 

 can live and hatch in temporary pools and in water too foul for any 

 fish to survive in. 



Cypris. Incorrectly known as "hardshell daphnia," cypris forms an 

 important article of fish diet. These Crustacea inhabit stagnant pools, 

 particularly those well stocked with decomposing vegetal matter. Al- 

 though capable of swimming freely they are more apt to remain close 

 to the bottom, but more especially to decaying wood. They are of a 

 dull, purplish black or reddish color about the size of an ordinary pin- 

 head. Inexperienced observers frequently mistake them for daphnia. 

 Fishes do not appear to be quite so fond of them as of daphnia, but 

 they are a good second choice. They are extremely hardy and will 

 withstand dense overcrowding in the foulest of water. Under favorable 



