Pest Control in an SPS Tank: Dipping Is Not Enough

Pest control is one of the most overlooked parts of keeping an SPS tank.

I understand why. Flow, lighting, water chemistry, stability, and bacterial issues already take up most of our attention. But pests are different. They physically eat coral tissue, and once they spread, they can destroy an SPS collection very quickly.

Dipping Is Only the First Step

Most reef keepers dip new corals and consider the job done. Unfortunately, dipping is only the first step.

A normal coral dip may remove exposed adult flatworms, but it does not kill their eggs. Red bugs, white bugs, and the much less common black bugs are also not reliably eliminated by standard dips.

My Quarantine Process

My process is simple.

Every new SPS coral is dipped with Two Little Fishies ReVive. I cut the bottom flat whenever possible, remove the original plug and unnecessary dead skeleton, and then place the coral in a quarantine tank.

After that, I observe it every day.

I look at the polyps, tissue, base, and branches. I check for bite marks, eggs, irritation, fading tissue, or anything that looks unusual.

Observe. Observe. Observe.

Observation is the most important part of pest control.

A dip only affects what is exposed at that moment. Your eyes may catch what survived, what recently hatched, or what was too small to notice when the coral first arrived.

When I find something suspicious on a new coral, I decide how important that coral is to me. Honestly, if it is replaceable, I often throw it away.

Losing one frag is much better than allowing a pest to spread through an established SPS system.

For an important coral, I may isolate it and use a prolonged potassium chloride treatment after it has recovered from shipping and is healthy enough to tolerate it. This is not something I do to a newly arrived, stressed coral.

A new coral normally stays in quarantine for about one month. Before it enters the main system, I inspect it again from every direction with a magnifying glass.

Only corals that I believe are healthy go into the display tank.

Does That Mean My Systems Are 100% Pest-Free?

No.

I cannot honestly promise that. Some pest stages are too small to see. Some do not leave obvious marks at first. There may also be pests that I have never encountered or would not immediately recognize.

The more I learn about pests, the more I understand how much I do not know.

Observation also does not stop after quarantine.

I spend about 15 minutes every day closely inspecting my SPS tanks. Yes, I use a magnifying glass. It probably looks a little obsessive, but those 15 minutes may be the most important pest-control work I do.

When you know how your corals normally look, small changes become easier to notice.

Treating Flatworms and Red Bugs

If I find signs of Acropora-eating flatworms, I remove the affected coral and dip it with ReVive for 15 minutes every three days, at least three times. Because dips do not kill the eggs, continued observation is still necessary.

For red bugs or similar pests, Interceptor may be needed. It is a prescription veterinary medication and is used off-label in reef tanks, so it should be obtained legally and used carefully. Even when my systems look completely healthy, I may still perform a preventive Interceptor treatment every three to six months. That comes from painful experience.

My Advice Is Simple

Quarantine when possible. Inspect everything carefully. Treat regularly.

But most importantly, observe your corals every day.

Observe. Observe. Observe.

Even without medication, early observation gives you options. You can remove one frag before the pest reaches the rest of the tank.

Dipping is just a step.

Observation is the real pest-control system.

New to SPS? Start with our Acropora Care Guide, then browse the SPS Corals collection.

Frequently Asked Questions

Does a coral dip kill pest eggs?
No. A dip like ReVive can remove exposed adult flatworms, but it does not kill their eggs — which is why repeat dips and daily observation matter.

How long should new coral stay in quarantine?
About one month. I observe it every day and inspect it again from every direction under a magnifying glass before it goes into the display tank.

How do you treat Acropora-eating flatworms?
Remove the affected coral and dip it in ReVive for 15 minutes every three days, at least three times, then keep observing — because the dip does not kill the eggs.

What treats red bugs?
Interceptor, a prescription veterinary medication used off-label in reef tanks (obtain it legally and use it carefully). I sometimes run a preventive treatment every three to six months.