What To Feed Corals In A Reef Tank – The Ultimate Guide To Vibrant
If you have ever stared at your reef tank and wondered if your corals are actually “hungry,” you are not alone. It is a common hurdle for every hobbyist, whether you are just starting with your first soft coral or managing a complex SPS-dominant system.
I remember the first time I added a Duncan coral to my tank; I was so worried about its health that I spent hours researching exactly how to keep it thriving. The good news is that understanding what to feed corals in a reef tank does not have to be a guessing game, and I am here to guide you through it.
In this guide, I will share the exact strategies I use at Aquifarm to promote explosive growth and neon-bright colors. We will cover everything from phytoplankton to target feeding techniques, ensuring your reef becomes the centerpiece you’ve always dreamed of.
Understanding How Corals Actually “Eat”
Before we dive into the specific foods, we need to talk about how these fascinating creatures consume energy. Corals are unique because they are mixotrophs, meaning they get their nutrition from multiple sources.
Most of the corals we keep in our home aquariums house microscopic algae called zooxanthellae within their tissues. These algae use photosynthesis to turn light into sugars, providing the coral with up to 90% of its daily energy needs.
However, that remaining 10% is where the magic happens. By providing supplemental food, you are giving your corals the proteins, lipids, and carbohydrates they need to build new skeletons and repair tissue.
The Role of Light vs. Food
Think of light as the coral’s “bread and butter” and supplemental feeding as its “protein shake.” While they can survive on light alone in some cases, they will never truly thrive or reach their full color potential without proper feeding.
When you provide external food, you often see a physical feeding response. This is when the polyps extend their tentacles to grab passing particles, which is one of the most rewarding sights for any reefer!
what to feed corals in a reef tank: A Breakdown of Food Types
Choosing the right menu for your reef can feel like walking into a five-star restaurant with a 50-page menu. To make it simple, we can categorize coral food into four main groups.
1. Phytoplankton (Microscopic Algae)
Phytoplankton are the “plants” of the ocean’s microscopic world. These are generally best for soft corals, clams, and the tiny organisms (like copepods) that live in your live rock.
I highly recommend using live phytoplankton if possible. It doesn’t just feed the corals; it helps stabilize the ecosystem by outcompeting “bad” algae for nutrients.
2. Zooplankton (Microscopic Animals)
This category includes rotifers, copepods, and brine shrimp nauplii. These are much meatier and are the preferred food source for many LPS (Large Polyp Stony) corals.
If you have corals with visible mouths, like Acanthophyllia or Micromussa, they will absolutely love chasing down these tiny swimming morsels. It’s like a steak dinner for them!
3. Particulate and Powdered Foods
Products like Reef Roids or Benepellets have become staples in the hobby for a reason. These are engineered to have a specific micron size that fits perfectly into coral polyps.
These powders are incredibly nutrient-dense. A little goes a long way, so be careful not to dump the whole jar in, or you’ll be fighting a hair algae breakout next week!
4. Amino Acids and Liquid Supplements
Corals can also absorb nutrients directly from the water column. Amino acids are the building blocks of protein and can significantly boost pigmentation and tissue growth.
I find that dosing amino acids is particularly helpful for SPS corals (Small Polyp Stony) which have very small mouths and rely heavily on absorption and tiny particles.
The Best Feeding Methods for Success
Knowing what to feed corals in a reef tank is only half the battle; how you deliver that food is just as important. There are two main philosophies here: broadcast feeding and target feeding.
Broadcast Feeding: The “Buffet” Approach
This is the easiest method. You simply mix your coral food into a cup of tank water and pour it into a high-flow area of the aquarium. The internal pumps then carry the food to every corner of the tank.
Pros:
- Very fast and easy.
- Feeds the entire ecosystem, including micro-fauna.
- Great for tanks with a high density of small corals.
Cons:
- A lot of food can get trapped in mechanical filtration or the sump.
- Increases the risk of overfeeding and high nitrates/phosphates.
Target Feeding: The “Precision” Approach
This is my favorite method for LPS corals. Using a turkey baster or a specialized coral feeder tool, you gently squirt the food directly onto the coral’s tentacles.
Pros:
- Ensures the coral actually eats the food.
- Less waste in the water column.
- Allows you to monitor the health of each individual coral.
Cons:
- Very time-consuming in large tanks.
- Can be stressful for the coral if the flow is too high or if the tool touches them.
Feeding Requirements for Different Coral Types
Not all corals are created equal. To get the best results, you need to tailor your feeding strategy to the specific species in your reef.
Soft Corals (Mushrooms, Leathers, Zoanthids)
These are generally the easiest to feed. Most softies rely heavily on light and dissolved organic matter. I usually stick to phytoplankton and amino acids for these guys.
Zoanthids, however, can be surprisingly “piggy.” If you target-feed them tiny organic particles, you will notice their “mats” spreading across your rocks much faster.
LPS Corals (Torches, Hammers, Brain Corals)
LPS corals are the most fun to feed because they have large, visible mouths. They love meaty foods like mysis shrimp, chopped krill, or specialized LPS pellets.
Pro Tip: Feed your LPS corals at night or about 30 minutes after the lights go out. This is when their feeding tentacles (called sweeper tentacles) are most extended.
SPS Corals (Acropora, Montipora)
SPS corals are the “divas” of the reef world. They have very tiny polyps, so they cannot eat large chunks of food. Instead, they thrive on micro-plankton and dissolved nutrients.
For SPS, consistency is more important than quantity. I prefer daily dosing of amino acids and a light broadcast feed of powdered food 2-3 times a week.
The Golden Rule: Balancing Food and Water Quality
One of the biggest mistakes I see beginners make is overfeeding. While it is tempting to feed your corals every day to see them grow, you must remember that whatever goes into the tank must eventually come out.
Excess food turns into ammonia, nitrites, and eventually nitrates and phosphates. High levels of these can lead to nuisance algae like GHA (Green Hair Algae) or, even worse, cyanobacteria.
Maintaining the Nutrient “Sweet Spot”
In a healthy reef tank, you want to maintain a low but detectable level of nutrients. I usually aim for:
- Nitrates: 5–10 ppm
- Phosphates: 0.03–0.10 ppm
If your nutrients are “bottomed out” (zero), your corals may pale or bleach because they are starving. If they are too high, your corals might turn brown as their zooxanthellae overpopulate.
When is the Best Time to Feed?
Timing is everything! Most corals in the wild are nocturnal feeders because that is when plankton rises to the surface of the ocean. In our tanks, we can mimic this.
I recommend feeding about 20 to 30 minutes after your lights dim for the evening. You will see the polyps start to “reach out” into the water. This is the optimal time to target feed.
However, if you are broadcast feeding phytoplankton, doing it during the day is perfectly fine, as it helps feed the organisms that rely on light as well.
Essential Tools for Feeding Your Reef
You don’t need a lot of gear, but a few specialized tools will make your life much easier and keep your hands out of the water (which is better for the corals!).
- Turkey Baster: The classic tool for target feeding and blowing detritus off rocks.
- Coral Feeder Tube: Long acrylic tubes that allow you to reach the bottom of deep tanks without getting wet.
- Feeding Ring: Great for keeping floating food from being sucked into the overflow immediately.
- Small Containers: For thawing frozen food in tank water before feeding.
Common Problems and How to Solve Them
Even with the best intentions, things can go wrong. Here are a few troubleshooting tips for your reef feeding journey.
The “Fish Thief” Problem
If you try to target-feed a Brain coral, your Cleaner Shrimp or Tangs will likely try to steal the food right out of the coral’s mouth. This can stress the coral and even damage its tissue.
The Solution: Feed your fish first. Once the fish are full and distracted, then move on to feeding the corals. You can also use a cut-off plastic soda bottle to cover the coral while it eats, protecting it from scavengers.
Cloudy Water After Feeding
If your water looks like milk after you feed, you are likely using too much powdered food. While some cloudiness is normal, it should clear up within an hour.
The Solution: Turn off your protein skimmer for 30-60 minutes during feeding to allow the corals to capture the food, but make sure to turn it back on to help clear the excess later.
FAQ: What to Feed Corals in a Reef Tank
How often should I feed my corals?
For most tanks, 2-3 times a week is the “sweet spot.” If you have a very nutrient-poor system (ULNS), you might feed daily. If your nitrates are high, scale back to once a week.
Can I feed my corals human food?
Technically, you can feed small pieces of raw, unseasoned seafood like shrimp or scallops. However, specialized aquarium foods are much safer as they are free from preservatives and are the correct size.
Do corals need to be fed to survive?
Most photosynthetic corals can survive on light and the waste produced by fish. However, they will not grow quickly or show their best colors without supplemental feeding.
Will feeding corals cause an algae bloom?
It can if you overdo it. Always monitor your phosphate levels. If you see algae starting to grow, reduce your feeding frequency or increase your water changes.
What is the best food for beginners?
I always recommend starting with a high-quality particulate food like Reef Roids and a bottle of live phytoplankton. These are easy to use and provide a broad spectrum of nutrition.
Conclusion: Happy Corals, Happy Hobbyist
Learning what to feed corals in a reef tank is one of the most rewarding parts of the reef-keeping hobby. It moves you from being just an observer to being an active participant in your reef’s growth and health.
Remember to start slow. It is always better to underfeed and gradually increase than to overfeed and spend weeks fighting hair algae. Watch your corals closely; they will tell you if they are happy by extending their polyps and showing off their vibrant colors.
Don’t be afraid to experiment with different brands and types of food. Every reef is a unique ecosystem, and part of the fun is finding the “perfect recipe” for your specific slice of the ocean. Happy reefing!
