How to feed a reef tank

I'm Darren. I've been culturing live marine food in Wales since 2008, and in that time I've spoken to thousands of reef keepers. The single most common conversation I have goes something like this:

Nine times out of ten, it isn't the water. It's the food. And more specifically, it's the pattern of how that food is being delivered to the tank.

This guide walks you through what a reef tank actually needs to eat, why a proper feeding routine matters more than any single product, and how to build a schedule that keeps every level of your tank nourished without turning feeding time into a second job.

Why feeding a reef tank is different

Most new reef keepers come from a freshwater or fish-only background, where feeding means sprinkling flake food on the surface once a day and watching fish eat it. A reef tank is a completely different system. You're not just feeding fish. You're feeding a whole food web.

In a healthy reef, everything eats. Your fish are the obvious part, but your corals are filter-feeding planktonic particles continuously through their polyps. Your copepods and amphipods are grazing on biofilm and microalgae. Your clams and feather dusters are pulling phytoplankton out of the water column. Your sponges, tunicates, and feather worms are processing fine particles 24 hours a day. Every one of those organisms needs something different, and most of them need it on a completely different schedule to your fish.

This is why a reef tank fed only on flakes and frozen cubes slowly declines even when the water parameters look perfect. The fish get enough. Everything else starves quietly.

The four categories of reef tank food

Before we get to the schedule itself, it helps to understand the four food groups that a complete reef tank feeding routine covers. Each one feeds a different part of the ecosystem.

1. Phytoplankton — the foundation

Phytoplankton is the base of the entire marine food chain. It's what copepods and rotifers eat, what clams and feather dusters filter out of the water, and what seeds the biological diversity that makes a tank feel alive. Dosed daily, live phytoplankton supports nutrient export, sustains copepod populations in your refugium, and feeds filter feeders directly. It's the single most overlooked element in most feeding routines, and the one that makes the biggest difference over a three to six month period.

2. Zooplankton — copepods and rotifers

Copepods and rotifers are the living prey that reef fish evolved to hunt. For mandarins, pipefish, wrasses, and seahorses, they're not optional. For everyone else, they trigger the kind of hunting and feeding behaviour that frozen food simply can't replicate. Copepods build a sustainable population in a refugium. Rotifers are essential for anyone raising fry, and they're a useful top-up for filter feeders and NPS corals.

3. Coral target foods

LPS corals, NPS corals, and filter-feeding invertebrates benefit from being fed directly. Oyster egg-based feeds, zooplankton concentrates, and reef juice blends deliver particles in the size range these animals actually capture and ingest. You don't need to target-feed every day, but a couple of times a week makes a visible difference to growth and colour.

4. Fish food

Dried and frozen food still has a place in the routine. I'm not going to tell you to throw out your pellets. What I am going to tell you is that if pellets are the only thing going into your tank, you're leaving most of the ecosystem unfed.

Why a schedule beats "feeding when you remember"

Here's the thing about reef tanks that nobody tells new keepers: consistency matters more than volume. A small, predictable daily dose of phytoplankton will do more for your tank over a month than a huge one-off addition every fortnight. The organisms you're feeding build populations around a reliable food supply. Take that supply away and the population contracts. Add a flood of food and you either waste it or spike your nutrients unnecessarily.

When I speak to keepers whose tanks are thriving, the common thread isn't that they're spending the most money on live food. It's that they've built a routine they can actually stick to. Same time each day. Same days each week for the things that don't need daily doses. Enough structure that it becomes automatic.

A written schedule also solves a subtler problem: it stops you from forgetting what you've already fed. Without one, it's easy to double up on some things and skip others entirely because you can't remember whether you dosed yesterday or the day before.

Building your routine in five steps

Common feeding mistakes I see all the time

Overdosing on day one

New keepers read a dosing rate, think "more must be better", and dose three or four times the recommended amount on the first day. This stresses your skimmer, can cloud the water, and doesn't feed the tank any faster. Start at the light end of any dosing range and build up over two to three weeks.

Dosing into high flow or straight onto the skimmer intake

Phytoplankton that goes straight into a skimmer gets pulled out before anything has a chance to eat it. Turn the skimmer off for an hour after dosing, or dose into a slow-flow part of the sump where the cells have a chance to distribute.

Feeding once and expecting instant results

Live food works cumulatively. You'll notice improved feeding response within 24 to 48 hours of a good copepod addition. You'll notice colour improvements in corals over two to four weeks. You'll notice a transformed microfauna community over three months. Be patient and trust the process.

Treating the routine as optional

A week of consistent feeding beats a month of sporadic overfeeding. If you can only commit to three days a week of live food, that's fine — just make sure those three days actually happen.

Where to go next

This guide covers the principles. The tools below turn those principles into something you can actually do tonight.