HOW TO DEAL WITH MARINE ICH IN THE SALTWATER AQUARIUM

The Spectrum of Coral Nutrition: Photosynthesis vs. Predation

Understanding what to feed starts with understanding how your corals eat. Most hobbyist corals are mixotrophs, meaning they derive energy from two sources: light and food. Through photosynthesis, zooxanthellae provide the coral with sugars and amino acids. However, corals also require nitrogen, phosphorus, and other trace elements that light alone cannot provide. For example, Large Polyp Stony (LPS) corals, such as the Duncan Coral or the Blastomussa, have large, fleshy mouths designed to consume chunky meaty foods. On the other hand, Small Polyp Stony (SPS) corals like Acropora have tiny polyps that are better suited for capturing microscopic plankton and absorbing dissolved organic compounds.

The mistake many beginners make is either over-relying on light or overfeeding the water column to the point of causing an algae bloom. A balanced approach involves providing high-quality lighting while supplementing with targeted feedings once or twice a week. Before you begin a heavy feeding regimen, it is vital that the process of cycling a fish tank is long finished and your biological filtration is robust enough to handle the increased nutrient load. Corals that are well-fed are more resilient to stress, such as minor temperature fluctuations or the accidental introduction of pests, because they have larger energy reserves stored in their tissues.

• LPS Corals: Prefer "meaty" offerings like mysis shrimp, chopped krill, or specialized coral pellets.
• SPS Corals: Thrives on fine particulate foods, liquid phytoplankton, and amino acid supplements.
• Soft Corals: Many, like Zoanthids and Palythoas, respond well to powdered reef foods and organic "dust."
• Non-Photosynthetic (NPS) Corals: Corals like the Sun Coral (Tubastraea) require daily manual feeding as they do not use light at all.

Methods of Delivery: Target Feeding vs. Broadcast Feeding

How you deliver food to your reef is just as important as what you are feeding. The two primary methods are broadcast feeding and target feeding. Broadcast feeding involves mixing liquid or powdered food into a cup of tank water and pouring it into the path of a powerhead. This mimics the natural flow of nutrients on a reef, allowing all inhabitants—including sponges, clams, and "clean-up crew" members—to grab what they need. However, this method can lead to high waste levels if the food isn't consumed quickly, potentially leading to the dangers of high ammonia, nitrite and nitrate that can poison the system.

Target feeding is the more precise (and often more rewarding) approach. Using a long pipette, a turkey baster, or a specialized "coral feeder" tube, you gently puff food directly onto the polyps of a specific coral. This ensures that the intended coral actually ingests the nutrients and reduces the amount of food that ends up rotting in the substrate. For LPS corals like the Scolymia or Brain Corals, watching the fleshy tissue fold over a piece of shrimp is one of the most fascinating sights in the hobby. For the best results, turn off your powerheads and return pumps for 10-15 minutes during target feeding to prevent the food from being washed away before the coral can secure it.

• The Pipette Method: Ideal for LPS corals; allows you to place individual shrimp or pellets into the coral's mouth.
• The "Bell" Method: Placing a cut-off plastic bottle top over a coral while feeding to prevent fish from stealing the food.
• Amino Acid Dosing: Best done via broadcast; these liquids stimulate coral feeding responses and enhance color.
• Night Feeding: Many corals extend their tentacles most fully after the lights go out; try feeding 30 minutes after sunset.

Compatibility and Care Considerations During Feeding

Feeding corals isn't just about the invertebrates; you must also consider the other residents of your tank. Many fish species are "food thieves." For instance, a greedy Yellow Tang or a group of Blue-Green Chromis will quickly learn that a pipette full of food means a free meal, and they will often pick the food right out of the coral's mouth, damaging the coral's delicate tissue in the process. Shrimp, particularly Peppermint Shrimp and Skunk Cleaner Shrimp, are notorious for reaching deep into coral polyps to steal a meal. To fix this, try "distraction feeding"—give your fish their normal flake or frozen food on one side of the tank before you begin target-feeding your corals on the other.

Furthermore, be mindful of the "stinging" capability of certain corals during feeding. When corals are in "feeding mode," they extend sweeper tentacles that are packed with nematocysts (stinging cells). If you have corals placed too close together, the excitement of feeding can trigger a chemical battle. Always ensure you are following the basics of fish compatibility and coral spacing to prevent your feeding routine from turning into an all-out war. If a coral stays retracted for several hours after feeding, it may be reacting to a sting from a neighbor or physical irritation from a fish.

• Distraction Feeding: Feed your fish first so they are too full to bother the corals.
• Protective Barriers: Use cages or covers for slow-eating corals like Sun Corals if you have aggressive scavengers.
• Glove Protection: Some corals, like Palythoas, contain palytoxin; always wear gloves when handling or feeding them.
• Flow Management: Always remember to turn your pumps back on after feeding to prevent oxygen levels from dropping.

The Risks of Overfeeding: Managing Nutrient Export

While feeding is beneficial, "too much of a good thing" is a very real danger in reef keeping. Every piece of coral food that is not consumed contributes to the organic load of the tank. Excess nutrients lead to high phosphates and nitrates, which are the primary fuels for nuisance algae like Green Hair Algae and Cyano-bacteria. Furthermore, high phosphate levels can actually inhibit the calcification process in stony corals, meaning that by trying to help them grow through feeding, you might accidentally be stunting their skeletal development if you don't maintain water quality.

To balance coral feeding with water purity, you must have a robust nutrient export system. This includes a high-quality protein skimmer, which removes organic waste before it breaks down, and regular water changes. Many successful reefers use a "low nutrient, high import" strategy: they keep the water very clean through aggressive filtration but feed the corals heavily and frequently. This provides the corals with the energy they need while the filtration prevents the water from becoming "swampy." Monitoring your parameters weekly with reliable test kits is the only way to ensure your feeding schedule is sustainable for the ecosystem.

• Protein Skimming: Ensure your skimmer is rated for at least the volume of your tank and is cleaned regularly.
• Mechanical Filtration: Change filter socks or floss shortly after a broadcast feeding to remove uneaten particles.
• Testing: If nitrates rise above 10ppm or phosphates above 0.05ppm, scale back feeding frequency.
• Refugium Use: Growing macro-algae like Chaetomorpha is an excellent way to soak up the excess nutrients from coral feeding.

Takeaway: Achieving a Thriving, Vibrant Reef

Feeding your corals is one of the most impactful ways to transition from a beginner to an intermediate reef keeper. By moving beyond the "light only" mindset, you provide your invertebrates with the building blocks they need for faster tissue growth, better healing, and the stunning fluorescent colors that make reef tanks so captivating. Whether you choose to target-feed your favorite LPS "Acan" or broadcast-feed a cloud of phytoplankton for your SPS colonies, the key is consistency and observation. Watch how your corals react, adjust your nutrient export to match your input, and always prioritize stability over rapid change. A well-fed reef is a healthy reef, and the effort you put into their nutrition will be rewarded with an underwater display that truly glows with life. Ready to find the perfect food for your specific inhabitants? Check out our latest equipment and supplement reviews at RateMyFishTank.com to ensure you are giving your reef the very best! Would you like me to help you create a customized weekly feeding schedule based on the specific corals you have in your tank today?