FEEDING FISH 217 



e\ Asellus aquaticiis, water louse. — Occurs in moderate numbers in 

 ponds, especially cool trout ponds. 



Waterfleas and cyclopses are easily reared in little side pools con- 

 nected with larger ponds. In the winter and early spring these are 

 covered with layers of manure, clay and compost to favor their propa- 

 gation. With the advent of warm weather, when the organisms have 

 multiplied sufficiently, they are admitted into the main pond by a con- 

 necting channel. Since all of these lower forms of life, but especially 

 the water fleas, are injured by even slight acid reaction of the medium 

 in which they are found, this danger should be averted by regular 

 "working" of the pond bottoms. 



b. The Larvae of Insects 



a^. Culex pipiens (stinging gnats) and several species of Anopheles 

 (mosquitoes). The larvae live among the vegetation of shallow pools 

 and ponds. They float just under the surface of the water with their 

 backs exposed to the air, breathing oxygen. When the water is agi- 

 tated they may be seen wriggling to the bottom. 



&\ Coretha. — The larvae are recognized by their transparent bodies. 

 They may be observed floating around in the water, apparently quite 

 motionless. 



c^. Chirononms. — This larva, recognized by its red color, lives in the 

 mud and slime of foul streams. 



d^. Ephemera, Cloe (day fly). — The mature insect often makes its 

 appearance in enormous swarms. The larvae require from two to three 

 years for development. 



e'^. Phryganeides. — The larva of the caddis fly inhabits a variety of 

 stagnant and flowing waters and secretes itself in structures which it 

 builds of sand, fragments of plants, stones, etc. 



To encourage the development of these insects and their larvae, Susta 

 had already recommended the planting of vegetation (basket willows) 

 on the borders of ponds. Gnats like to swarm in warm air but not in 

 direct sunlight. 



II. Spawn and the young progeny of Mollusca, among which might 

 be mentioned the small bivalves which are usually found attached to 

 sticks, stones and similar obects ; Limnsea or pond snails, which are a 

 favorite food of fish; Planorbis (snails with discoidal shells), and Pal- 

 udina (pond snails with operculated shell). They subsist chiefly upon 

 vegetation and slime and do not molest other animal life which serves 

 as food for carp. When not present in carp ponds they should be 

 introduced. Lime spread over and worked into the bottom of ponds 

 favors their rapid development. 



To promote the development of the lower forms of life which serve 

 as food for fish, pond fertilization is practiced. The primary object of 

 fertilization is to furnish food for the lower pond flora, although some 



