Feeding Corals In A Reef Tank – A Complete Guide To Vibrant Growth
Do you ever look at your reef tank and wonder if your corals are truly reaching their full potential? We all want those vibrant colors and explosive growth rates that make a display tank truly breathtaking.
I know exactly how it feels to worry if your “frags” are getting enough nutrition or if you are accidentally over-polluting your water. The good news is that mastering the art of feeding corals in a reef tank is one of the most rewarding skills you can develop as an aquarist.
In this guide, I am going to walk you through everything I have learned over the years about coral nutrition. We will cover the best types of food, the most effective techniques, and how to keep your water crystal clear while doing it.
Understanding Why Corals Need to Eat
It is a common misconception that corals get 100% of their energy from light. While it is true that the symbiotic algae (zooxanthellae) inside their tissues provide sugars through photosynthesis, corals are still animals.
Think of light as their “bread and butter,” but actual food as their “protein and vitamins.” Without external nutrients, corals can survive, but they rarely thrive or show those deep, rich pigmentations we love.
In the wild, the ocean is a “soup” of organic matter. By feeding corals in a reef tank, we are simply trying to replicate the nutrient-rich environment of a natural coral reef within our glass boxes.
The Role of Heterotrophy
Heterotrophy is the process of an organism consuming organic substances for energy. Corals use their stinging cells, called nematocysts, to grab passing particles from the water column.
When you provide external food, you are giving the coral the building blocks it needs for tissue repair and skeletal growth. This is especially important for Large Polyp Stony (LPS) corals that have massive “mouths” designed for catching prey.
Even Small Polyp Stony (SPS) corals, which many think only need light, benefit immensely from microscopic particles. They use their tiny polyps to capture bacterioplankton and dissolved organic compounds.
Choosing the Right Food for Your Reef
Walking into a fish store can be overwhelming because there are dozens of different “magic potions” and foods on the shelf. Don’t worry—most of them fit into a few simple categories.
The key is to match the size of the food to the size of the coral’s polyps. If the food is too big, the coral can’t eat it; if it is too small, it might just float away and rot.
I always recommend keeping a variety of foods on hand. Just like us, corals benefit from a diverse diet that covers different amino acids and fatty acids.
Phytoplankton and Micro-Foods
Phytoplankton are microscopic plants that form the base of the food chain. While most corals don’t eat phytoplankton directly, it feeds the “pods” and micro-fauna in your tank that corals do eat.
Liquid amino acids are another essential tool. These are not “food” in the traditional sense, but they act as a signal to the corals to open their polyps and prepare for a meal.
I like to dose amino acids about 15 minutes before I actually feed. It is like ringing the dinner bell for your reef, ensuring every coral is ready to catch what you offer.
Zooplankton and Meaty Foods
This is where the fun begins! For your LPS corals like Acans, Scolymia, and Euphyllia (Torches and Hammers), you want something they can really grab onto.
Mysis shrimp, brine shrimp, and chopped krill are fantastic options. These “meaty” foods provide the protein needed for rapid tissue expansion and vibrant coloration.
If you have a mixed reef, look for specialized “reef roe” or particulate coral foods. These blends often contain a mix of sizes that can satisfy everything from a tiny Acropora to a hungry Fungia plate coral.
Methods of Feeding Corals in a Reef Tank
There are two primary ways to get food to your corals: broadcast feeding and target feeding. Both have their pros and cons, and I often use a mix of both depending on the day.
Choosing the right method depends on your equipment, your coral stocking list, and how much time you have to spend on maintenance. Let’s break down how to do both effectively.
Remember, the goal is to get the food into the coral, not into the corners of your aquarium where it will just turn into nitrates and phosphates.
The Broadcast Feeding Technique
Broadcast feeding is the “shotgun” approach. You simply mix your food in a cup of tank water and pour it into the flow of your powerheads.
This is the easiest method and is great for Small Polyp Stony (SPS) corals and soft corals like Xenia or Leathers. It ensures that every inch of the tank gets a little bit of nutrition.
However, the downside is that a lot of food goes to waste. It can get stuck in your mechanical filtration or settle behind your rockwork, which might lead to algae issues if you aren’t careful.
The Target Feeding Technique
Target feeding is the “sniper” approach. Using a turkey baster, a long pipette, or a specialized syringe, you gently puff food directly onto the coral’s polyps.
I highly recommend this for expensive or slow-growing LPS corals. It ensures they actually get the meal and prevents your greedy fish from stealing the food right out of the coral’s mouth!
To do this effectively, turn off your return pump and powerheads. Let the water become still, then slowly place the food over the coral. Wait about 10-15 minutes before turning the flow back on.
When and How Often Should You Feed?
Timing is everything when it comes to feeding corals in a reef tank. Most corals are actually more active at night when their natural predators (and the sun) are away.
If you look at your tank after the lights go out with a red flashlight, you will see “feeding tentacles” extending from corals that looked smooth during the day. This is the optimal time to feed.
Feeding at night can also help prevent fish from stealing the food, as many reef fish go to sleep in the rockwork once the lights dim.
Establishing a Routine
For most reefers, feeding 2 to 3 times a week is the “sweet spot.” This provides enough nutrition for growth without overwhelming your biological filtration.
If you have a very “clean” tank with zero nitrates and phosphates, you might need to feed daily. If you are struggling with hair algae or cyanobacteria, you should probably cut back.
Always watch your corals for feedback. If they look “puffy” and extended, they are happy. If they are staying retracted, they might be getting too much (or too little) input.
Targeting Specific Coral Types
Not all corals are created equal. A “one size fits all” approach rarely works in a diverse reef aquarium. You need to understand the specific needs of your inhabitants.
Let’s look at the three main categories of corals and how to best provide them with the nutrients they crave for that “ultra” look.
By tailoring your approach, you can ensure that even the most finicky species in your collection stay healthy and colorful.
Feeding Large Polyp Stony (LPS) Corals
LPS corals are the “big eaters” of the reef. Species like Scolymia, Acanthastrea, and Lobophyllia have very distinct mouths and can consume surprisingly large pieces of food.
I love feeding these guys pieces of enriched Mysis shrimp. Watching a Scoly fold inward to swallow a shrimp is one of the coolest parts of the hobby!
Be careful not to overfeed “meaty” foods to LPS. If the piece of food is too large, it may rot inside the coral before it can be digested, which can lead to infections.
Feeding Small Polyp Stony (SPS) Corals
SPS corals, like Acropora and Montipora, prefer very fine particulate matter. They thrive on “reef snow,” powdered foods, and liquid supplements.
For these corals, I find that broadcast feeding a high-quality powdered food is the most effective. The tiny polyps act like a net, catching the dust-sized particles from the water.
Regularly dosing amino acids is also a game-changer for SPS. It encourages the polyps to stay extended during the day, which helps them capture more light and nutrition.
Feeding Soft Corals and Zoanthids
Soft corals and Zoanthids are generally more forgiving. Many of them absorb dissolved organic matter directly from the water through their skin.
However, Zoanthids and Palythoas definitely appreciate a direct meal. Target feeding them with a fine liquid food once a week can lead to much faster colony growth.
Leathers and Toadstools don’t usually need target feeding, but they will benefit from the “leftovers” in the water column after you feed your other corals.
Managing Water Quality While Feeding
The biggest challenge with feeding corals in a reef tank is the “nutrient tightrope.” You want enough food for the corals, but not so much that you grow a forest of algae.
Every bit of food you put in the tank eventually breaks down into ammonia, nitrite, nitrate, and phosphate. Managing this waste is the key to long-term success.
Don’t be discouraged if your levels spike a bit after a heavy feeding; the goal is to have a filtration system that can process that spike quickly.
The Importance of a Good Protein Skimmer
A high-quality protein skimmer is your best friend when you are feeding heavily. It removes organic compounds before they break down into nitrates.
I usually leave my skimmer running during feeding, but some people prefer to turn it off for an hour to let the food circulate. Just don’t forget to turn it back on!
If you notice your skimmer cup filling up with dark, smelly “gunk” after a feeding session, that means it is doing its job and protecting your water quality.
Using Chemical Media
If you find that your phosphate levels are creeping up despite regular water changes, you might want to use GFO (Granular Ferric Oxide) or a phosphate-removing resin.
Carbon is also excellent for removing the “yellowing” compounds that can build up when you use a lot of liquid coral foods. It keeps the water clear so your lights can penetrate deeper.
Always test your water parameters weekly. This allows you to adjust your feeding frequency before a small problem becomes a massive algae outbreak.
Essential Tools for the Job
You don’t need a lot of expensive equipment to feed your corals, but having a few specific tools makes the process much easier and more precise.
I have a “feeding kit” that I keep under my stand so everything is ready to go when it’s time for dinner. This saves time and prevents me from getting lazy with my routine!
Invest in these basics, and you will find that feeding corals in a reef tank becomes a relaxing part of your day rather than a chore.
- Turkey Baster: The classic tool for target feeding and blowing detritus off rocks.
- Long Pipettes: Great for reaching deep into the tank without getting your arm wet.
- Feeding Cylinder: A clear tube you can place over a coral to keep fish away while it eats.
- Small Containers: For thawing frozen food in tank water.
Frequently Asked Questions
Can I overfeed my corals?
Yes, absolutely. While the corals themselves might not “overeat,” the excess food will rot in the tank. This leads to high nitrates, phosphates, and eventually nuisance algae or coral bleaching.
Do I need to feed corals if I have a high fish load?
If you have many fish and feed them heavily, your corals may get enough nutrition from the fish waste (poop) and leftover scraps. However, direct feeding still provides a significant boost to growth.
What is “Reef Snow”?
Reef snow is a term for particulate organic matter that falls through the water column. You can buy commercial versions or make your own by blending various coral foods into a fine mist.
Should I turn off my filters when feeding?
Yes, I recommend turning off your return pump and mechanical filters (like fleece rollers or socks) for 15-30 minutes so the food stays in the tank for the corals to catch.
How do I know if my corals are eating?
Look for “polyp extension.” If the coral’s tentacles are out and grabbing at the water, it is actively hunting. After feeding, you might see the coral “fold” or “shrink” as it moves food to its mouth.
Conclusion
At the end of the day, feeding corals in a reef tank is about observing your animals and responding to their needs. There is no perfect “manual” because every tank is a unique ecosystem.
Start slowly, experiment with different foods, and always keep an eye on your water chemistry. You will soon notice that your corals are more vibrant, grow faster, and are much more resilient to stress.
The journey of a reef keeper is one of constant learning. By providing the right nutrition, you are giving your underwater garden the very best chance to flourish. Happy reefing!
