All of these places teem with life. Walk around any natural body of water. Hidden under the surface, uncountable algae and diatoms, plankton and copepods feed the burgeoning billions of invertebrates. Insect larva and naiads scuba dive, carrying water bubbles or breathing through snorkels. Boatmen and back swimmer beatles row their long legs looking down or up to find their prey.
Water spiders build bubble nests to house their young.
Caddis fly larva construct their cases from plant debris or grains of sand, and some catch prey by casting sticky nets. To be small and live in a pond is the most dangerous thing in the world. One must be very quick and clever to live long enough to reproduce. And reproduction is a megabusiness in the pond. Bluegill females can lay up to 67,000 eggs.