Feeding for Reef Aquariums: How-To Guide | Myreeflog

Introduction: Why Feeding Matters for Reef Health

Feeding in reef aquariums is more than dropping in pellets. It is a core husbandry practice that fuels fish metabolism, supports coral growth through heterotrophy, and feeds the microbial loop that keeps nutrients cycling. Done well, feeding builds color, vigor, and resilience. Done poorly, it drives nuisance algae, cyanobacteria, and dull polyp extension. This task guide explains how to plan, portion, and execute feeding for a thriving mixed reef.

Corals are not plants. Even photosynthetic corals supplement energy by capturing planktonic foods and dissolved organics. Fish waste and finely particulated food become nutrients for corals and filter feeders. Balanced feeding promotes stable nitrate and phosphate within acceptable ranges, healthy bacterial populations, and stronger coral tissue. Consistency is key, and platforms like My Reef Log help you standardize your routine and visualize the impact over time.

When and How Often to Feed

Fish Feeding Frequency

• Most reef fish: 1-2 small feedings per day. Offer what the fish consume in 2-3 minutes for frozen or 30-60 seconds for pellets.
• High metabolism species (anthias, chromis): 2-4 small feedings daily. Auto feeders are helpful for mid-day portions.
• Carnivores (wrasses, hawkfish): 1-2 feedings daily, focus on meaty foods such as mysis and LRS blends.
• Herbivores (tangs, rabbitfish): Provide a sheet of nori daily (5-10 cm strip per medium tang), plus small pellet feedings.
• Optional fasting day: 1 day per week with no feeding can help stabilize nutrients in established tanks.

Timing: Feed during the photoperiod when fish are most active. If doing multiple feedings, space them 4-6 hours apart. For nocturnal or shy fish, a small evening feeding when lights are dim can help ensure they eat.

Coral Feeding Frequency

• SPS corals (Acropora, Montipora): Benefit from fish-associated microfoods and bacterioplankton. Optional broadcast feeding 1-2 times per week using very fine foods (5-200 microns). See the SPS Corals Care Guide for Reef Tanks | Myreeflog for spectrum and flow considerations.
• LPS corals (Acanthastrea, Euphyllia, Trachyphyllia): Target feed 1 time per week. Offer small meaty items or a fine slurry. Avoid large pieces that can rot.
• NPS corals (sun corals, gorgonians, chili corals): Feed daily to several times per day with fine particulate foods and small meaty items. These corals rely almost entirely on heterotrophy.

Corals tend to extend feeding tentacles at night or when flow is moderate. Schedule coral feedings 30-60 minutes after lights ramp down, or when you regularly see polyp extension.

What You'll Need: Equipment and Supplies

• Foods:
  • Pellets or flakes for daily feedings (e.g., New Life Spectrum, TDO Chroma Boost, Ocean Nutrition). Choose pellet sizes that match fish mouth size.
  • Frozen foods for variety (PE Mysis, LRS Reef Frenzy, Hikari Mysis, Calanus, Cyclops). Rinse before use.
  • Nori sheets for herbivores (Two Little Fishies, Ocean Nutrition), plus a magnetic clip.
  • Coral microfoods (Reef Roids, Reef Chili, Reef Nutrition ROE/Oyster Feast, Benepets) and amino acids or vitamin boosters (Selcon, Vitamarin M) as optional enrichments.
• Tools:
  • Auto feeder for dry foods (Eheim Everyday, Hydros WiFi Feeder, Neptune AFS).
  • Fine mesh sieve (53-200 microns) for rinsing thawed foods.
  • Target feeding tool (Julian's Thing, long pipette or turkey baster), small mixing cups, and measuring spoons.
  • Flow control: the ability to pause return pump and adjust powerheads to low for coral target feeding.
  • RO/DI water for thawing and rinsing frozen foods.

Preparation checklist: confirm food is fresh and not freezer-burned, pellets are kept dry and sealed, auto feeder drum is clean and humidity free, and tools are rinsed and air dried after use.

Step-by-Step Feeding Process

1. Estimate portions. As a starting point, feed 0.5-1.0 percent of total fish biomass per day. Example: 200 g of fish mass in a 75 gallon tank equals 1-2 g of food daily. Adjust by observation and nutrient trends.
2. Thaw frozen foods in RO/DI water for 5-10 minutes. Use a sieve to strain, then rinse with additional RO/DI. Rinsing removes dissolved phosphate and fine organics that quickly cloud water.
3. Optional enrichment. Soak thawed foods for 10 minutes in a vitamin and HUFA supplement (e.g., Selcon) for improved fish nutrition, and amino acids for coral response. Do not overuse - a few drops are sufficient for 1-2 cubes of food.
4. Set tank flow. For fish-only feedings, leave return and skimmer on. For coral target feeding, pause the return pump and skimmer for 20-45 minutes and reduce powerheads to a gentle, alternating flow. Keep at least one powerhead running to maintain oxygenation.
5. Offer nori. Clip a 5-10 cm strip for tangs and rabbitfish. Remove any leftover after 2-4 hours to avoid decay.
6. Broadcast feed for fish. Add a small portion of pellets or thawed food near high flow so it disperses. Observe consumption. If food remains after 3 minutes, you fed too much - reduce next time.
7. Broadcast feed for corals (optional). For SPS and filter feeders, a fine slurry works best: 1/8 teaspoon coral powder food in 50-100 mL tank water, stirred well. Dispense across the tank, then wait 5 minutes to see polyp extension.
8. Target feed LPS and NPS. Using a pipette, gently deliver small amounts directly over mouths or polyps. Examples: 1-3 mysis per larger LPS head, or 0.1-0.2 mL of fine slurry per polyp for acans and blastos. Avoid blasting tissue with strong jets.
9. Observe and clean up. Remove uneaten chunks with a net or siphon. Restore return and skimmer after 20-45 minutes. Replace or rinse mechanical filtration if it collected heavy food debris.
10. Review performance. If fish are aggressive or slow eaters get nothing, split the next feeding into more, smaller portions. If corals ignore food, adjust timing closer to their natural feeding window or reduce particle size.

Why each step matters: rinsing reduces nutrient spikes, flow control prevents foods from being immediately sent to the sump, and staged, small portions align with fish physiology and reef microbial processing capacity.

Best Practices and Common Mistakes

• Vary the diet. Alternate between pellets, frozen, and nori. Rotating brands and particle sizes improves nutrient coverage and reduces dietary gaps.
• Use small, frequent feedings for high-metabolism fish. Anthias and small wrasses do better with 3-4 micro portions than one big feeding.
• Match pellet size to fish. Oversized pellets are spat and wasted. Choose 0.5-1.0 mm pellets for small fish, 1.5-2.0 mm for larger tangs and angels.
• Do not pour thaw water into the tank. It often carries extra phosphate and fine organics. Rinse and discard the soak liquid.
• Avoid starving corals in ultra-low nutrient systems. If nitrate is persistently below ~1 ppm and phosphate below ~0.02 ppm, consider slightly heavier feeding or reduced export so corals have access to nutrients.
• Watch oxygen at night. Heavy late-night feedings can depress dissolved oxygen as bacteria metabolize organics. Maintain surface agitation and avoid turning off all flow.
• Balance import and export. Increase refugium photoperiod, skimmer efficiency, or add a small water change if nutrients creep up.
• Auto feeder placement and calibration. Keep the drum dry, test 1-2 clicks into a cup to see actual pellet output, and mount so pellets drop into high flow away from the overflow.
• Do not force feed corals. Overstuffing LPS leads to regurgitation and tissue stress. Small, frequent portions are better than large meals.
• Sanitation matters. Rinse feeding tools after each use and deep clean weekly to prevent bacterial buildup.

How Feeding Affects Water Parameters

Feeding adds organic nitrogen and phosphorus to the system. Fish and microbes transform these inputs into nitrate and phosphate. Too little and corals pale; too much and algae blooms. The goal is a steady, moderate range with balanced import and export.

• Nitrate (NO3): Target 2-15 ppm for most mixed reefs. Heavier fish loads often stabilize around 5-10 ppm. After a large feeding, a 0.5-2 ppm rise over 24-48 hours is common. Learn more in the Nitrate in Reef Tanks: Complete Guide | Myreeflog.
• Phosphate (PO4): Target 0.03-0.10 ppm. Rinsed frozen foods typically add a small bump, about 0.01-0.03 ppm per feeding in mid-sized systems. Guidance for control strategies is in the Phosphate in Reef Tanks: Complete Guide | Myreeflog.
• pH and alkalinity: Post-feeding microbial respiration can lower pH by 0.05-0.15 within hours, especially at night. Keep alkalinity stable at 7.5-9.0 dKH. As coral growth increases with better nutrition, alkalinity consumption may rise.
• Dissolved oxygen (DO): Feeding increases biological oxygen demand. Keep strong surface agitation and skimming. Aim for DO above ~7 mg/L in reef tanks.
• ORP: Expect a temporary drop after feeding as organics rise. ORP recovers as the skimmer and bacteria process the load.
• Temperature: Large frozen food portions can slightly chill small systems. Allow thawed food to reach room temperature before feeding to avoid minor thermal swings.

Tip: If nutrients trend too low (NO3 below ~1 ppm, PO4 below ~0.02 ppm), slightly increase feeding frequency or reduce export. If nutrients trend high, reduce portion sizes by 10-20 percent, increase export, or swap a feeding for a nori-only session.

Scheduling and Tracking

Consistency beats intensity. Build a schedule and adjust based on observation and data. An example weekly pattern for a 75 gallon mixed reef with moderate fish load:

• Mon-Fri: 2 feedings per day - morning pellets, evening small frozen mix. LPS target feed Wednesday evening.
• Sat: Light feeding, nori for herbivores, and a small broadcast of fine coral food at night.
• Sun: Optional fasting day if nitrate and phosphate trend upward.

Use My Reef Log to set recurring reminders for daily fish feedings, mid-week coral target feedings, and auto feeder refills. Log the food type and estimated portion size, then review nutrient charts weekly to correlate portions with NO3 and PO4 trends. If you make a change, annotate it so you can see how the system responds over 7-14 days.

Advanced tip: For anthias and other grazers, program an auto feeder to deliver micro portions midday, then manually feed a small frozen mix in the evening. Track pellet clicks per feeding in My Reef Log so you can precisely adjust if nutrients drift.

Conclusion

Thoughtful feeding turns a good reef into a great one. Small, consistent portions, high quality varied foods, and a clear plan for nutrient export create stable conditions where fish and corals flourish. Observe, measure, and adjust rather than guess. With My Reef Log, you can schedule routines, document portions, and connect feeding decisions to nutrient trends, coral response, and overall tank health.

FAQ

How much should I feed my reef fish each day?

Start at 0.5-1.0 percent of total fish biomass per day, split into 1-3 small feedings. Practically, offer what your fish finish within 2-3 minutes for frozen or 30-60 seconds for pellets. If nitrate and phosphate climb past your targets, reduce portions by 10-20 percent and reassess over one to two weeks.

Should I rinse frozen foods?

Yes. Thaw in RO/DI water for 5-10 minutes, then strain through a fine mesh and discard the soak liquid. Rinsing reduces dissolved phosphate and fine particulates that can spike nutrients and fuel film algae.

When is the best time to feed corals?

Feed when polyps are extended and flow is gentle. Many corals extend more at night. For mixed reefs, a small broadcast feeding after lights ramp down works well. For LPS target feeding, pause the return and skimmer for 20-45 minutes so food stays in the display.

Are auto feeders good for reef tanks?

Yes, especially for stable, small mid-day feedings and vacation coverage. Choose a reliable model, keep pellets dry, and calibrate the number of clicks or drum rotations. Combine auto feedings with a small manual frozen feeding for variety.

Should I turn off my skimmer when feeding?

For fish-only feedings, leave the skimmer on. For coral target feedings, pausing the skimmer and return for 20-45 minutes keeps food in the display and prevents immediate removal. Maintain at least some circulation to preserve oxygen levels. If skimmate production surges after feeding, slightly lower the skimmer water level to prevent overflow.

Further reading: Control nutrients while feeding well with the Nitrate in Reef Tanks: Complete Guide | Myreeflog and the Phosphate in Reef Tanks: Complete Guide | Myreeflog. For coral-specific needs, see the SPS Corals Care Guide for Reef Tanks | Myreeflog.