What Is Zooplankton?

Zooplankton are tiny drifting animals found in all marine environments — and they’re vital to healthy reef ecosystems. Unlike phytoplankton, which produce energy through photosynthesis, zooplankton consume microalgae, detritus, and other small organisms, and in turn, serve as food for corals, filter feeders, and fish.

They’re part of the base of the food chain and are especially important in reef tanks that house picky eaters or juvenile marine life.

Common Reef-Friendly Zooplankton

These are the most beneficial and commonly encountered types of zooplankton in reef systems:

• Copepods
  Small crustaceans like Tisbe, Tigriopus, Parvocalanus, and Apocyclops. They're high in fatty acids, constantly reproduce, and feed fish, corals, and invertebrates.

• Rotifers
  Microscopic and nutrient-rich, rotifers are widely used in aquaculture. They’re ideal for coral larvae, fry, and filter feeders.

• Mysid Shrimp (Mysids)
  Larger than copepods, mysids are active swimmers and excellent live food for fish. They also help clean up detritus.

• Amphipods
  Small, shrimp-like scavengers that live in rockwork and substrate. Amphipods provide live food and improve biodiversity.

• Isopods (Reef-Safe Types)
  Some free-living isopods help consume detritus and contribute to the microfauna population in a balanced tank.

• Larval Invertebrates
  Many reef-safe inverts (like snails, shrimp, and crabs) release planktonic larvae into the water column — a natural zooplankton source that feeds corals and filter feeders.

Why They Matter in Reef Tanks

• Natural Nutrition – Live zooplankton provide protein, fatty acids, and movement that trigger feeding responses

• Support Coral Health – Particularly for LPS, softies, and non-photosynthetic corals

• Aid Fish Fry Development – Many marine fry won’t eat prepared food early on

• Maintain Biodiversity – A stable tank depends on a variety of microfauna working together

• Enhance Water Quality – Many zooplankton feed on detritus and suspended particles

In Summary

Zooplankton are more than just live food — they’re a cornerstone of healthy reef ecosystems. From copepods and rotifers to mysids and amphipods, these tiny animals support coral growth, fish development, and overall tank balance.

Encouraging a strong zooplankton population — or supplementing with trusted live cultures — can make a noticeable difference in reef vitality.