Aiptasia Anemone | Aquarium Friend or Foe?

Woke up to find your reef tank overrun with small, brownish to translucent anemones? You’re not the first: it has happened, or will happen, to almost every aquarist at some point. That’s why today in FantaSEA’s Friend or Foe series, we’re discussing Aiptasia anemones and what to do about them.

Are these anemones bad? Should you remove them, and if so, how? Find out everything you need to know below!

What is an Aiptasia anemone?

Aiptasia anemones belong to the family Aiptasiidae. They’re naturally found throughout much of the world’s oceans, both tropical and temperate, where they live on hard surfaces like rocks. They survive by catching organic particles with their tentacles, and can also photosynthesize thanks to a a symbiotic relationship with unicellular algae.

These super-tough anemones, which can survive a range of water parameters and salinities, are pretty interesting. They’ve been used as model organisms for a range of different types of scientific studies, like on ecotoxicology, coral bleaching, and much more.

Unfortunately for us aquarists, their hardy nature also makes Aiptasia anemones (sometimes referred to as glass anemones) highly invasive. Outside their natural habitat—and away from their natural predators—some Aiptasia species can easily overrun a tank.

The main suspects in the aquarium hobby are called Aiptasia pulchella and Exaiptasia pallida (formerly Aiptasia pallida). Only a small piece of these is needed to cause an infestation, and since they’re found throughout aquarium stores, live rock, and pretty much everywhere else, it’s very easy for that single piece to reach your tank.

Aiptasia: Aquarium friend or foe?

Aquarists in general, and saltwater aquarists in particular, are used to random bits and bobs showing up in their tanks. Live rock, a cornerstone of most tanks, can contain all sorts of hitchhikers: worms, sponges, snails, starfish, crabs, shrimp, and much more.

Some hitchhikers, like algae-eating snails and water-filtering sponges, are considered welcome additions. Others not so much! Unwelcome hitchhikers include stinging fireworms, destructive gorilla crabs, and, indeed, some species of anemone.

Aside from the pretty but invasive majano anemone, the most common unwelcome anemone hitchhiker is Aiptasia. They can pop up seemingly overnight, covering large swathes of the tank in extreme cases. They multiply very rapidly and compete aggressively for resources like food or space.

So, unfortunately, Aiptasia is an aquarium foe. Aside from being unsightly, it can sting nearby corals. Severe infestations can kill off entire reefs, and ironically, attempting to remove the anemones can actually make the situation infinitely worse.

Getting rid of Aiptasia

If you’ve spotted mature Aiptasia anemones in your tank (up to 2″ tall), you can safely assume it has already been overrun. Baby polyps are growing all over the place as we speak!

Trying to remove polyps can be disastrous: they can regrow from tiny pieces. If you leave just a smidgen of the base upon removal, multiple Aiptasias will grow back. Additionally, these anemones will actually start multiplying rapidly when they feel threatened.

Bizarrely, they can even try to escape, as anemones aren’t completely stationary. They possess the ability to detach themselves and swim or crawl if they feel their current spot isn’t safe anymore.

How do you kill Aiptasia if you can’t cut it into pieces?! This question has long plagued the aquarium community. Sure, if a polyp is on a loose piece of rock, you can just take that out of the tank and dip it in freshwater for an instant kill. But what if the rock also has coral, or if it can’t be moved at all?

Injection

Folks have come up with a number of inventive solutions. These generally involve injecting the anemones with an acidic or alkaline agent in order to kill them without triggering the dreaded mass multiplication.

Get yourself a 10ml syringe and try the following:

• Boiling hot water: can work if the anemone is easy to target, but be careful not to burn yourself or any corals.
• Lemon juice: a quick jab deep into the anemone should work. Don’t overuse it, as it can alter the water parameters in small tanks.
• Freshwater: worth a try since it’s free! Aiptasia can’t handle rapid salinity changes and will die from osmotic shock when injected with enough freshwater.
• Kalkwasser: normally used to maintain calcium and alkalinity levels, this alkaline solution will also kill Aiptasia when injected.
• Aiptasia-X: calcium-based and formulated to block off the anemone’s mouth.
• Frank’s F-Aiptasia: calcium-based and formulated to cause tissue disintegration.
• Joe’s Juice: calcium-based and formulated to cause tissue disintegration.

Now, all this sounds pretty straightforward, but unfortunately it’s not. Aiptasia anemones usually grow in small holes, cracks, and crevices. They can quickly retreat into these when they feel threatened, making it difficult to inject them properly, especially when the polyps are small.

Dealing with an Aiptasia infestation thus requires a lot of patience—and maybe a little help from a natural extermination squad.

Natural predators

Despite the tentacles of these anemones being riddled with stinging nematocysts, some fish and invertebrates do have a taste for Aiptasia.

Here at FantaSEA Aquariums, we normally recommend against adding new creatures to your tank for the sole purpose of eradicating a certain pest. It should only be done if the aquarist is aware that success isn’t guaranteed, and if the critter in question matches the existing ecosystem and won’t outgrow the aquarium.

In this case, there’s a great option available, a creature many of us like to keep in our tanks regardless of the presence of Aiptasia. It’s called the peppermint shrimp, Lysmata wurdemanni (or consider its less common cousin, L. boggessi).

These shrimp don’t need much space to thrive, making them a suitable option for nano tanks. Although some can develop a taste for coral, they’re mostly considered reef safe, and they’re positively ravenous for tasty Aiptasia. They’re our first line of defense against these annoying anemones!

Aside from peppermint shrimp, some creatures you could consider enlisting include:

• Berghia nudibranchs: probably actually the most effective Aiptasia killer of all, but unfortunately they will die off once the infestation has been dealt with, since that’s all they eat.
• Copperband butterflyfish (Chelmon rostratus): beautiful and hungry for Aiptasia, but quite finicky and best reserved for experienced aquarists.
• Bristletail filefish (Acreichthys tomentosus): a small (up to 3.5″) and funky-looking reef fish with a taste for Aiptasia, which can do well in tanks of 30+ gallons.

Need help?

A thriving reef aquarium is one of the most spectacular additions you can make to your home or office, but unfortunately, there’s always the potential for problems to pop up. An Aiptasia infestation is one of the most common issues in saltwater fishkeeping.

Want a fish tank but worried you lack the time or expertise to maintain it? That’s where we come in! Contact FantaSEA Aquariums with your ideas and our team will design, set up, and maintain your aquarium for you.