In a freshwater pond, it's "eat or be eaten." A dragonfly larva eats a midge; a water beetle larva eats a damselfly larva. Snail larvae grow. A beetle larva eats one. Up close, we see the eating apparatus of a damselfly larva—with a retractable hook beneath mandibles. Some creatures bite and chew, others suck. A water beetle larva holds on to its prey, injects a poison that turns the victim's insides to soup, and then sucks it dry. We watch one eat a damselfly larvae and then another water beetle larva. Some have ingenious ways to camouflage themselves, like the water scorpion, and to breathe air while hunting under water. Caddisfly larvae hide in debris, then eat.
Freshwater Assassins (1947) is a documentary movie in France. It was directed by Jean Painlevé. With a runtime of 24m, the film averages 6.5/10 across 16 TMDB ratings.
MyFlixer streams Freshwater Assassins in HD from several servers. Click Watch Now, select a server, and enjoy the full movie without subscriptions or pop-up sign-up forms. If you like documentary movies, Chadwick Boseman: A Tribute for a King, Avatar: The Deep Dive - A Special Edition of 20/20 and Trainwreck: The Real Project X are worth adding to your list.