Target-Feeding Corals: When and How

Photosynthetic corals get most of their energy from light and zooxanthellae, but many grow and color up better when fed. Learn target-feeding for LPS, broadcast feeding for SPS and softies, food choices, and why non-photosynthetic corals must be fed frequently.

Light plus food

Most reef corals host symbiotic algae called zooxanthellae, which photosynthesise and can supply up to about 85% of the coral's nutritional needs — carbohydrates, amino acids, vitamins and fatty acids. But that alone is not optimal. Corals are also active feeders (heterotrophs): they capture zooplankton, phytoplankton, bacteria and dissolved organic matter, often at night when polyps extend. Corals that are fed consistently show noticeably better colour, growth and polyp extension.

Target-feeding versus broadcast feeding

How you feed depends on polyp size. Large-polyp stony (LPS) corals such as Acanthastrea and Scolymia are target-fed: turn down the flow, and place a meaty morsel or a sinking pellet directly onto the polyp so it can grab and swallow it. Corals with tiny polyps — SPS and many soft corals — are better broadcast (dispersion) fed, by dosing fine suspended foods such as phytoplankton or powdered coral food into the water column, ideally near a pump so it disperses across the tank.

• Meaty foods (mysis, adult brine shrimp, fish eggs/roe): for LPS and other larger-polyp corals.
• Prepared coral foods: pellets and powders such as ReefRoids and Oyster Feast — sinking types for LPS, long-suspending powders for filter feeders.
• Phytoplankton and fine particulates: for SPS and filter-feeding corals with very small polyps.
• Micro foods (rotifers, copepods, Artemia nauplii, Calanus): for tiny-polyp and non-photosynthetic species.

The flip side is overfeeding. Every bit of food that misses a coral becomes dissolved nutrients, and excess feeding can trigger algae, cyanobacteria or bacterial blooms and encourage pests. Feed deliberately — small, targeted amounts — and keep your nutrient export (protein skimming and water changes) keeping pace so the extra food grows corals, not problems.

Sources: reefbuilders.com , www.coralmagazine.com , reefbuilders.com