172 NATURE-STUDY 



Watch the fish in the aquarium. Place some food in the 

 water and observe them feeding. Watch the predaceous 

 kinds catch water insects, etc. Most fishes are carnivorous, 

 and even cannibalistic. Among them the general rule is 

 that the bigger swallows the smaller. Aquatic insects, 

 worms, crayfish, etc., and the minute animalcula that swarm 

 in the water, are also food of the carnivorous fish. Some 

 are vegetarian and feed on aquatic plants. 



In cleaning fish in the spring or early part of the summer 

 one often finds masses of roe. This roe is the unlaid eggs of 

 the fish. Fish lay their eggs or spawn generally in the spring, 

 soon after the ice is out of the lakes and ponds. At this time 

 they often make long journeys or migrations to a suitable 

 place for the spawning. They go up the rivers and streams 

 to the headwaters, and there the female deposits her eggs. 

 Some fish dig in the sand at the bottom of the water a shal- 

 low hollow in which the eggs are placed. Sometimes they 

 are covered with a little sand, sometimes they are loosely laid 

 in the water. The little stickleback makes a pretty little 

 nest in which the female lays her eggs. Some fish take care 

 of the eggs until they are hatched, and then for a time protect 

 the young. But many kinds pay no further attention to the 

 eggs after they are hatched. The young, or "fry," as they 

 are called, and the eggs as well, are much attacked by fishes 

 and other animals. In this connection read to the children 

 The Story of the Salmon, in "Science Sketches," by David 

 Starr Jordan, a very dehghtful and sympathetic study of the 

 life of a fish. Show the boys that it is wrong to catch or 

 spear fish before the spawning season is passed. 



Bring out the economic aspect of the subject. This would 

 be well done in connection with geography. The fishing 



