Phytoplankton Feeding Guide

This guide covers phytoplankton reef feeding with practical steps for home aquariums. Phytoplankton feeds filter-feeding corals and clams — valuable when dosed in moderation to tanks that actually consume it.

For related reading, see aquarium water chemistry, aquarium filtration, Blackworms vs Tubifex and Yellow Tang.

Who Benefits

Non-photosynthetic corals, gorgonians, some soft corals, sponges, and tridacnid clams capture phytoplankton from the water column. Most SPS corals rely primarily on light and zooplankton.

Fish-only reef tanks gain little from phytoplankton unless you keep dedicated filter feeders.

Commercial Products

Refrigerated live blends (Nannochloropsis, Tetraselmis, Isochrysis) ship cold and store weeks refrigerated. Shake before dosing near powerheads for dispersion.

Frozen concentrates offer convenience but verify coral response — not every tank needs daily phytoplankton.

Dosing Strategy

Start with manufacturer minimum while monitoring nitrates and phosphate. Overdosing clouds water and fuels nuisance algae without helping corals.

Target feed with pipettes near specific colonies when possible instead of broadcasting tank-wide if only a few specimens need it.

Home Culture Overview

Advanced keepers culture green water in separate vessels with light and f/2 fertilizer, then harvest to the display. Requires sterile technique to avoid contaminating display with crash blooms.

Most hobbyists achieve better results buying fresh cultures than maintaining lab-grade algae on a kitchen counter.

Signs of Overfeeding

Persistent haze, rising phosphate, and cyano on sand suggest too much plankton or inadequate export. Pair feeding with skimming, water changes, and refugium harvest.

If corals show no feeding response after a month of dosing, reallocate budget to lighting and flow improvements.