Many different animals eat algae, from tiny plankton to big fish and turtles, in both freshwater and saltwater systems.

Quick Scoop

  • Tiny grazers like zooplankton and planktonic crustaceans are some of the first algae eaters in aquatic food webs.
  • In ponds and streams, tadpoles, snails, shrimp, and small fish scrape or suck algae off rocks, plants, and glass.
  • In aquariums, popular “algae eaters” include plecos, otocinclus, Siamese algae eaters, loaches, snails, and shrimp.
  • In the ocean, blennies, tangs, hermit crabs, sea urchins, and some turtles graze on various algae types, from films to seaweed.

Main groups that eat algae

  • Fish – Plecostomus, bristlenose pleco, otocinclus, Siamese algae eater, Chinese algae eater, kuhli and hillstream loaches, various blennies and tangs in saltwater.
  • Invertebrates – Shrimps (like Amano, ghost, cherry), many snails (nerite, ramshorn, apple, Malaysian trumpet), hermit crabs, other small crabs.
  • Other aquatic animals – Tadpoles, some turtles (e.g., sea turtles, sliders), sea urchins, Antarctic krill, and other small grazers.

Simple food‑web picture

At the base, algae capture sunlight and grow. Small grazers (zooplankton, snails, shrimp) eat the algae, then fish and larger animals eat those grazers, passing the energy up the food chain.

Information gathered from public forums or data available on the internet and portrayed here.