How to Dip Corals (and Why You Should Never Skip It)

Every coral that lands in your tank has spent time outside a controlled reef system — in a bag, a cooler, a delivery truck, or someone else’s holding tank. That’s true whether it came from us, a local fragger, or a big online vendor. Pests, parasites, and bacteria don’t care how reputable the seller is, and a coral that looks perfectly healthy can still be carrying something that won’t show up for weeks. Dipping is cheap, fast insurance against that risk, and it should happen every single time, no exceptions.

Why You Should Dip Every New Coral, No Matter Where It Came From

Flatworms, red bugs, nudibranchs, vermetid snails, and bacterial infections from shipping stress are the most common hitchhikers, and all of them can hide in a coral’s base, folds, or polyps where you’d never spot them with the naked eye. Even careful vendors who dip before shipping can’t guarantee zero risk after a coral has traveled. Dipping on arrival isn’t an insult to the seller — it’s standard practice for anyone serious about protecting their system, and it takes ten minutes versus months of dealing with an outbreak in your display tank.

Iodine Dips: Lugol’s Solution & Iodine-Based Conditioners

Lugol’s solution is a strong disinfectant, which makes an iodine dip one of the best options for treating bacterial infections and conditions like brown jelly disease. It’s also the go-to dip for freshly cut frags, since a fresh cut is an open wound and iodine helps sterilize it before infection can set in. Because Lugol’s is potent, always dilute strictly to the product label — this is not a dip to eyeball.

Melafix: Tea Tree Extract for Bacterial Infections

Melafix (the Marine formula only — never the freshwater version) is a botanical, tea-tree-based antibacterial that’s reef safe and gentle enough to use on corals and anemones. It’s best for general bacterial infections rather than being a pest killer. Expect polyps to close up tight within seconds of exposure — that’s a normal reaction, and they’ll reopen once the coral is back in clean water.

Hydrogen Peroxide: Best for Zoas, Algae, and Biofilm

Zoanthids are among the most tolerant corals to hydrogen peroxide, which makes a peroxide dip an excellent tool for stripping hair algae, dinoflagellate biofilm, and general grime off zoa colonies. You’ll see the solution bubble on contact with organic matter — that’s the peroxide oxidizing whatever it’s breaking down, and it’s a good sign the dip is working. SPS and LPS are more sensitive to peroxide than zoas, so if you’re dipping stony corals, use a weaker dilution and watch closely rather than assuming the same strength is safe.

Revive by Two Little Fishies: The All-Around Everyday Dip

Revive is a plant-extract based dip that’s gentle enough to be a great first-line treatment for every new arrival. It does a solid job knocking loose pods, common flatworms, algae, and general debris from a coral’s surface, and it’s formulated to support tissue recovery rather than just kill pests. Gently swirl or agitate the coral while it soaks to help dislodge anything hiding in the folds. For a known heavy pest outbreak, pair Revive with a stronger, more targeted dip rather than relying on it alone.

Reef Primer & Other Coral Conditioner Dips

Products like Reef Primer and Seachem Reef Dip fall into their own category: iodine complexed with a protective slime coat that clings to the coral’s tissue, holding the treatment in contact with an infected or stressed area longer than a plain iodine dip would. That slime coat also helps block re-infection at the treatment site. These are a solid broad-spectrum choice for fresh frags or any coral that’s showing non-specific signs of stress.

Potassium Permanganate: A Last Resort for Acropora RTN/STN

Potassium permanganate is a serious, aggressive oxidizer that some SPS growers reach for when an Acropora is actively losing tissue (RTN or STN) and milder dips haven’t stopped it. It is not a routine dip — the margin between an effective treatment and burned, discolored tissue is narrow, and it should only be used after gentler options have failed, and only by exact label dosing. Reach for this when a coral is already crashing, not as a “just in case” step on a healthy frag.

Freshwater Dips: Powerful Against Flatworms and Nudibranchs, but Risky

A freshwater dip works through osmotic shock — the sudden change in pressure ruptures the cells of soft-bodied pests like flatworms and nudibranchs almost instantly. The catch is that the same osmotic pressure is hard on coral tissue, and freshwater is one of the fastest ways to kill a coral if it’s left in too long. Use dechlorinated water matched to your tank’s pH and temperature, keep the dip to 15–30 seconds, and pull the coral immediately if you see tissue puffing or sloughing. This one is best reserved for a confirmed flatworm or nudibranch problem, not routine dipping.

Dip Times at a Glance

• Revive (Two Little Fishies): 5–10 minutes — everyday pest and debris dip for any new arrival
• Lugol’s / iodine dips: 15–30 minutes — infections, brown jelly, fresh frag wounds
• Melafix (Marine): 3–5 minutes max — bacterial infections
• Hydrogen peroxide (3%): 3–10 minutes — zoas, hair algae, biofilm
• Reef Primer / conditioner dips: follow label, typically 10–15 minutes — general conditioning
• Potassium permanganate: last resort only, exact label dosing, not for routine use
• Freshwater dip: 15–30 seconds max — flatworms and nudibranchs only

The Rinsing Process: Never Skip This Step

After any dip, transfer the coral to a separate cup or container of clean, tank-temperature saltwater and let it rinse for about a minute before it goes anywhere near your display or frag tank. This clears off residual dip chemical along with any dead or dying pests, so none of it ends up back in your system. If you run a quarantine tank, that’s the ideal place for a newly dipped coral to sit for a week or two — it gives you time to watch for anything that didn’t show up on day one before the coral joins your main display.

The Bottom Line

Dipping takes ten minutes and costs a few dollars. Skipping it can cost you the whole tank if a hitchhiker gets established. No matter who you’re buying from — us included — dip every new coral before it touches your main system, rinse it well, and give it a little quarantine time if you can. Have a question about which dip fits your situation? Reach out and we’re happy to help, or browse our current WYSIWYG picks.

Dip Every Time, Even From a Trusted Source

It’s tempting to skip the dip on a frag from a friend or a store you trust, but pests don’t discriminate based on reputation — Aiptasia, flatworms, and red bugs travel on healthy-looking coral from good sources just as easily as anywhere else. Make the dip a non-negotiable step for every single piece that enters your system, no exceptions, and you’ll avoid the vast majority of pest introductions before they ever become a problem.