How to Dip New Corals: A Ruthless Pre-Entry Protocol

Every pest infestation in your tank — every flatworm plague, every zoa spider, every montipora-eating nudibranch outbreak — walked in through the front door on a coral you added. Reef tanks have no other meaningful entry point. That is the brutal, liberating fact behind coral dipping: you control the border, and a ten-minute protocol at the border prevents problems that can take a year to eradicate once inside. This is the ruthless version of that protocol. It assumes every coral is guilty until proven clean, including frags from your best friend's immaculate tank.

Why trusted sources still get dipped

The frags most likely to skip inspection are exactly the ones from trusted sources — the LFS you love, the club member with the showpiece reef. But pests do not respect reputations: acropora-eating flatworm eggs are nearly invisible, zoa spiders are camouflage artists, and a healthy-looking colony can carry eggs without symptoms. The dip rule only works as an absolute: everything gets dipped, no exceptions, no matter the source. The one-time cost is minutes; the cost of the exception is measured in months.

The station

Set up next to the tank, before the coral arrives:

• Three containers: dip bath, rinse one, rinse two, each filled with display water (pull it during the water change you were due for anyway)
• A coral dip solution — the standard pest dips target flatworms, zoa spiders, bristleworm hitchhikers, and most crawling arthropods
• A small powerhead, turkey baster, or pipette for blasting the coral during the dip
• Bright flashlight and a magnifier or phone macro lens
• Bone cutters and glue from a fragging kit for plug removal
• Nitrile gloves — always, and non-negotiable if zoanthids are involved

The protocol, step by step

1. Float and equalize. Temperature-acclimate the sealed bag in the tank or a bucket for 15-20 minutes. Skip long drip acclimation for most corals — they tolerate reasonable salinity differences far better than extended sitting in fouling shipping water.

2. Never let shipping water touch your tank. It carries parasites, pest larvae, and whatever the coral shed in transit. It goes down the drain, every time.

3. Inspect before dipping. Under the flashlight, examine the coral and especially the plug: egg spirals (flatworms, nudibranchs), sesame-seed bumps on acro branches (AEFW eggs look like scattered pepper), webbing, tiny crabs in branch axils, sundial snails at zoa mat edges. Knowing what came in shapes how aggressively you treat.

4. Dip. Mix the dip per its label in the first container. Submerge the coral and set a timer — typically 5-10 minutes depending on product and coral type. Every minute or two, blast the coral from all angles with the baster. Watch the bottom of the container: flatworms, spiders, pods, and worms drop off and accumulate. This debris field is your border-control x-ray.

5. Rinse twice. Swirl the coral vigorously in rinse one, then rinse two, blasting again. Dip residue and stunned pests both stay behind.

6. Remove the plug. This is the step most people skip and the step that matters most. Pest eggs ride on plugs and bases far more than on tissue, and no dip reliably kills eggs. Cut the coral off its plug, or chip away all dead skeleton and mounting material, and remount on your own clean plug. For encrusted frags where removal is impossible, scrub every exposed dead surface with a toothbrush in the rinse water.

7. Quarantine if you can; observe hard if you cannot. A separate quarantine tank held for four to six weeks catches egg hatches that no dip stops — it is the gold standard, especially for acropora. Without one, place new corals in an observable spot and inspect weekly with the flashlight, because you are relying on early detection instead.

Reading the fallout

The container bottom after a dip tells you what to do next:

• Nothing but mucus and a pod or two: normal. Proceed.
• Flatworms: assume more arrived elsewhere in the shipment; re-dip everything from that order in a week.
• Zoa spiders or nudibranchs: re-dip that coral every 5-7 days for three sessions to catch hatching eggs.
• Crabs: identify before executing — most acro crabs are beneficial symbionts worth keeping; gorilla crabs are not.

Log what you find by source. A store whose frags consistently dip dirty deserves your skepticism; one that dips clean for a year has earned the reputation people wrongly grant by default.

What dips do not cover

Honesty about limits: standard dips do not kill pest eggs, do not treat bacterial infections like brown jelly, and do not remove aiptasia or hydroid polyps riding on plugs — physical removal and plug replacement handle those, and our aiptasia guide covers the anemone problem in full. Dips also stress corals; a freshly dipped LPS may sulk for days. That is normal and vastly preferable to the alternative. If a new coral stays closed well beyond a week, run the checklist in why corals refuse to open before blaming the dip.

FAQ

Can I dip every type of coral?

Nearly all — softies, LPS, and SPS all tolerate standard pest dips at label strength. The exceptions worth researching first are the most delicate acropora fresh from long shipping and anything visibly shedding tissue; a half-strength shorter dip is a reasonable compromise for a coral already in distress.

How long should a coral dip last?

Follow the label — typically 5 to 10 minutes. Longer is not better; dip stress rises faster than kill rate. Repeated dips a week apart beat one heroic marathon session, because the repeat catches what hatched in between.

Do I need to dip corals from a fellow hobbyist's established tank?

Especially those. Hobbyist tanks run without quarantine more often than stores, and a stable infested tank shows no symptoms while producing carrier frags continuously. The rule works only when it has no exceptions.

Ten minutes at the border, every coral, every time — that is the entire secret to a pest-free reef. For the complete stocking workflow this protocol slots into, see our guide to coral care and propagation.