Coral pests can quickly wreak havoc on a thriving reef tank if left unchecked. In this guide, we identify the 10 most common coral pests—including flatworms, nudibranchs, aiptasia, and more—and provide safe, effective removal methods. Learn how to spot early signs of infestation and protect your corals with proven prevention and treatment strategies every reef keeper should know.
Coral pests can decimate your collection, spreading quickly and silently. Early detection and action are critical. Many pests:
Feed on coral flesh or polyps
Lay eggs invisibly
Hitchhike on new frags
Are resistant to dips alone
| Coral Type | PAR Range | Flow Type | Placement |
|---|---|---|---|
| SPS | 250–400 | Strong | Top |
| LPS | 75–150 | Moderate | Middle |
Pest | Appearance | Affects | Removal Strategy |
|---|---|---|---|
Montipora-Eating Nudibranchs | White, frilly-bodied slug | Montipora corals | Manual removal, dip daily, quarantine |
Acropora-Eating Flatworms (AEFW) | Tan, flat oval worms | Acropora SPS | Coral dips, turkey baster, UV sterilizer |
Red Planaria (Flatworms) | Rust-red teardrops | LPS, softies | Flatworm Exit, siphon out, carbon filtration |
Zoanthid-Eating Spiders | Tiny white/clear spiders | Zoas, palys | Manual removal, Bayer dip, QT |
Sundial Snails | Spiral shell w/ dark lines | Zoas, palys | Remove on sight, check for eggs |
Vermetid Snails | Hard tubes on rock, release slime | All corals | Super glue shut, crush or chip off |
Aiptasia | Transparent glass anemone | All corals | Inject with Aiptasia-X, Berghia nudibranchs |
Majano Anemones | Green bubbly anemone | All corals | Laser, kalk paste, peppermint shrimp |
Bristleworms (overpopulated) | Red/pink segmented worm | LPS tissue | Manual removal, trap at night |
Brown Jelly Infection (BJD) | Brown ooze on LPS | LPS (esp. Euphyllia) | Cut off infected heads, iodine dip, increase flow |
🧪 Always isolate infected coral and treat in a separate container.
Product | Effective Against | Use Instructions |
|---|---|---|
Bayer Advanced Insect Killer | Nudis, flatworms, spiders | 4 ml per cup of tank water, 10–15 min dip |
ReVive Coral Cleaner | Worms, bacteria | Gentle dip for 5–7 mins |
CoralRX Pro | Broad-spectrum | 20 drops per 1 cup water, 10 min |
Lugol’s Iodine | BJD, bacterial |
Every coral, even aquacultured, should be quarantined for 2–4 weeks.
During QT:
Inspect daily with magnifying glass
Dip every 3–5 days
Monitor for eggs or larvae
Maintain stable light and parameters
Keep separate tools for QT and DT
Turkey baster (for blowing pests off)
Coral tweezers
Magnifying glass
Coral dip container
Super glue (for vermetids)
Coral cutters (for fragging away infected tissue)
Symptom | Possible Cause |
|---|---|
Bite marks or missing polyps | Nudibranchs, spiders |
Closed polyps, no feeding | Flatworms, high stress |
Slime or brown strings | Brown Jelly Disease |
Sudden tissue recession | AEFW or bacterial infection |
Egg sacs on frag plugs | Nudibranch or sundial reproduction |
Isolate infected coral
Perform aggressive dip and rinse
Inspect nearby corals
Check rockwork and frag plugs
Repeat treatment over several days
Consider increasing flow and adding UV sterilizer
Pests are one of the biggest hidden threats in reef keeping. With proper quarantine, dipping, and daily inspection habits, you can prevent major outbreaks and maintain a clean, healthy reef.
Dream World Corals ensures all WYSIWYG corals are visually inspected and dip-ready, but we still recommend a home QT for maximum safety.
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Dream World Corals is a trusted online coral retailer specializing in hand-selected, ethically grown WYSIWYG corals. With an unwavering commitment to reef health, we provide hobbyists of all levels with premium corals backed by expert care, safe shipping, and our industry-leading 72-hour live arrival guarantee. Our mission is simple: help your reef thrive.
