The most popular live food for aquarium fishes is Daphnia. Daphnia includes several species, the largerst of which is D. magna. D. magna can reach a size of 1/5 of an inch in diameter. Each pregnant Daphnia female delivers up to fifteen babies (all are females under good conditions) every three days (depends on food, temperature, and water condition). Daphnia are heavy filter feeders and eat a wide variety of tiny organisms of appropriate size. Daphnia can be used to clear the green water of aquariums and large outdoor ponds without using dangerous chemicals. All Daphnia species produce large black (resting) eggs under certain conditions. The resting eggs survive frost and dryness. For fishes up to 4 inches.