A Proven Method for Treating Bacterial Infection in Anemones

Recently I had an urge to get back into keeping anemones and planned on setting up an anemone-specific aquarium with the 90-gallon tank I resealed. I knew I wanted to start looking at what has been out in the market recently and understand in what state of health they have been received at the local fish stores.

Based on the symptoms I saw—gaping mouths, deflated bodies, and some that looked okay but experienced inflate/deflate cycles—I researched what is needed to save these beautiful creatures and give them a fighting chance. Anemones in general are typically poor shippers, so it’s prudent to do our best to care for them as soon as possible.

I stumbled upon an awesome old thread on one of the popular forums from 2014 by Minh (OrionN), which outlined his “Protocol for using antibiotics to treat infected anemones.” Working with other anemone enthusiasts, he documented a treatment method that utilizes one of the commonly available antibiotics named Ciprofloxacin (Cipro). Two other alternatives were mentioned, but I will focus on Cipro.

Basic Hospital Tank Setup

Figure 1: Basic Hospital Tank Setup

Materials needed

  • 10-gallon tank
  • Small powerhead
  • 50w heater
  • Plastic basket from the dollar store (I personalized this since it made it easier to transport the specimen in and out of the tank.)
  • Small plastic container sized to hold the anemone basket temporarily with water
  • High-output, full-spectrum lighting (I used my old metal halide fixture.)
  • Ciprofloxacin tablets (Comes in 250 mg or 500 mg tablets and ordered online.)
Figure 2: Basket secured by an old Hydor Koralia magnet mount.

Basket secured by an old Hydor Koralia magnet mount.


Minh described his procedure as 7 x 24-hour cycles in tank water with 250 mg of Cipro dissolved in it. Start the treatment at an evening time since light will degrade the antibiotic over time.

  1. Fill tank with salt water, and maintain temperature and salinity. (I used water from my display tank in order to achieve a daily 10-gallon water change and get it used to my system water parameters.)
  2. Dissolve 250 mg of the antibiotic tablet by rubbing it with your fingers in front of the powerhead.
  3. Place/acclimate the specimen into the basket within the tank.
  4. Aim enough flow toward the anemone, but not direct laminar flow. (My basket helped disperse the flow and provided removable fastening surface during water changes.)
  5. Turn on the lights and leave on for 12 out of 24 hours in the morning.

Repeat the cycle with a 100% water change and a new dosage of 250 mg of Cipro daily. Use only the light to supplement energy to the anemone since you cannot feed during this period. If the anemone discharges waste early within any 24-hour cycle, an additional water change and dosage need to be done to keep the ammonia level low.

Depending on the seriousness of the infection, the key symptom to look for is when the anemone stops deflating and stays plumped up with a tight mouth. If 3 “blackout periods” go by and the mouth is still not tight, you may need to increase the daily dosage to 500 mg of antibiotic.


Minh warned to keep the treatment up for at least 3 days after the anemone stops deflating since ending the process too early can result in the infection returning and the bacteria now immune to the original dosage you had just performed. It’s pretty much the same instructions my doctor gives me when I need antibiotic treatment.

I had the anemone in the basket for a week in my main display tank but then noticed the inflate/deflate cycle occurring. The anemone stayed relatively semi-deflated most of the time. Anemones usually go through an inflate/deflate cycle to expel wastes, but this caused some concern since the mouth started to gape.

Below are photos of my Heteractis magnifica going through the treatment (Days 1-7), and it’s literally a lifesaver! Note that on Day 1 the mouth was very loose and it started to expose its guts.

Day 1 of the antibiotic treatment

Day 1 of the antibiotic treatment

Anemone treatment Days 2-4

Anemone treatment Days 2-4

The final stretch of anemone bacterial infection treatment process (Days 5-7)

The final stretch of anemone bacterial infection treatment process (Days 5-7)

After the treatment was completed, I shut off the wavemaker and transferred the anemone to my 125-gallon display tank on a pedestal. I set this up specifically so the Heteractis magnifica would be close to the surface of the water where it would receive the maximum PAR and highest exposure to flow.

H. magnifica anemone  placed in my 125-gallon reef aquarium

H. magnifica anemone placed in my 125-gallon reef aquarium

A tip for maintaining a healthy anemone: Feed some high-protein foods (shrimp, scallops, silverside pieces, etc.), cut to the size of its mouth, once to twice per week.


This is a great method for curing anemones of bacterial infections, and I want to thank Minh and others who have contributed to discovering this and shared their experience. My experience is just another data point to show that it works, and I hope more people will be aware and use this method to prevent unnecessary losses of prized specimens.

A 125-gallon reef aquarium display, the final home for the post-treatment anemone

My 125-gallon reef aquarium display, the final home for the post-treatment anemone


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About Ellery Wong

Ellery is a mechanical systems engineer at a Fortune 500 technology company. He has professional automation experience in the automotive, appliance, printing and robotics industries, as well as over 25 years as a saltwater aquarium hobbyist. He currently maintains a 365-gallon SPS/LPS system while regularly traveling for work, which presents a variety of challenges he enjoys tackling.


  1. Matt Bowers (Muttley000) says

    Great article Mr. Wong, thank you for writing it! My question is how do you determine this treatment is or isn’t needed? Do you feel all incoming nems are compromised and should be treated? If not should all imported specimens be treated, how about splits from a local fellow reefer?

    • Hi Matt,

      Thanks for the comment and question. Just from my personal experience I have been treating all my anemones ever since I started doing this treatment a few months ago. I am currently on day 4 of my next LTA. I have also been able to save a Lime BTA a month ago since I got lazy and figured it looked healthy enough with a tight mouth at the store but seemed to have started rotting on one edge and losing tentacles after having it for a week. What appeared healthy at the store can still have a hard time transitioning into your system and that’s when I think they are susceptible the most.

      Like quarantining fish and dipping corals I have learned the hard way that if I could prevent it I should do it. It’s always the one time I don’t do it that something bad happens. I would say if you do treat the anemone it would have a more than just a 50/50 shot chance of survival.

      As far as splits from fellow reefers I think those are still hardier, just like LPS/SPS frags, tend to be hardier since they are already used to an enclosed environment. The ones at the LFS, pending the source, can be tran-shipped or poorly packaged so it can look ok for the first few days after arrival but will eventually waste away through the week if a bacterial infection sets in and nothing is done about it.
      I’m in a process of building up a dedicated anemone tank so I’ve been doing this quite often recently.
      Cheers and Happy reefing!

  2. Thank you for this! I had my Heteractis Magnifika for almost 2 month now, this last 2 weeks it’s been in a bad shape, with this inflate/deflate issues, mouth open often and are starting to rotten on the edges loosing tentacles. Problem is it’s still glued with the foot on a rock, it’s a big rock so can’t remove it, any idea how I will make it let go, cuz I want to put it in quarantine and give the cipro there.

    • Ellery F Wong says

      Hi Zandra,
      One thing you can try is to try to get it to release the rock by rubbing the foot with an ice cube and then once you get an edge off use your fingers to gently massage and lift it.

      Good luck!


  3. Corbin Mandrell says

    I just received my Magnifica 3 days ago and started treating today in a QT tank. So I’ve read both your article and Minh’s article and he said he would treat for 12 hours then remove the anemone and place it in another QT tank with no treatment for 12 hours and then treat for 12 hours and so on, so did you do this method or did you treat for 24 hours?

    • Ellery F Wong says

      Hi Corbin,
      I Only had 1 Tank but I made sure to wash with some hot water and scrubbed it each time I did the daily water change. I think the key was to make sure any bacteria that is on the system doesn’t transfer over. Sure mine was not as sterile but it still worked for me.

      Good luck!

      • Corbin Mandrell says

        Thank you for getting back with me! Hopefully things go well and I will for sure let you know how everything went.

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