Aiptasia is one pest that I've always been paranoid about.
In my own tanks, I've only used dry rock to start and never take trades from local reefers that include anemones or coral attached to a rock that I can't easily remove. I do this to avoid many pests but most of all, aiptasia.
If I'm in a local store with aiptasia in their tanks, I won't buy frags from there. You never know where one is hiding and if there's evidence of some (or many) elsewhere, I just assume there's one on that frag plug I'm looking at.
Over cautious? Maybe. But, as a result, I haven't had to deal with it in years until recently.
A neighbor of mine was tearing down his tank so I took it over as a project here at the cove. He had suffered a major tank malfunction and the remaining inhabitants were saved in a small twenty gallon tank.
There were some gems in there. Huge mushrooms, zoas, a red Monti, a huge green elegance, and some small buds of Euphyllia that survived. It also had quite a bit of aiptasia.
My usual ritual in this case is to remove the coral and bleach the rocks. In this case, the rocks were so overgrown with soft corals, I never could have done it without a killing many of them. So, I decided to set it up as it's own project and answer the question, "Could I reverse this aiptasia invasion?"
The answer ended up being a resounding ,"yes!" and this is how I did it.
I don't find using it appealing. It may work for a single one but I'm not interested in fighting a daily battle by injecting each and every little anemone with poison in my tank.
So, after dismissing that idea, I decided to go the natural route. I've not been a fan of peppermint shrimp since watching one tear apart a prized torch. So, I started with an aiptasia eating file fish.
Aiptasia Eating File Fish
The file fish is an interesting one. I never would have looked at one without thinking I needed it to solve a problem. They're ugly - mottled brown with "hairs" all over their bodies. They seem to barely move in the fish store.
However, after getting one into this tank, I've developed an affinity for this little guy. He seems to effortlessly glide on the current and has quite the curious personality. A little timid but friendly. He's a keeper.
He's also not a solution to this problem. He was in this tank for weeks, picked on the rocks, but I never once saw him eat a single aiptasia.
Maybe he was too small/immature yet. Maybe he was eating the little ones. Either way, he wasn't the solution to this growing problem.
My research brought me back to peppermint shrimp but I was hesitant. I read stories about shrimp that passed over aiptasia just to destroy Euphyllia, lobos, and mini-carpet anemones.
As I mentioned earlier, I've watched in horror as one destroyed a torch worth 15-20 peppermint shrimp. Lesson learned.
This tank did contain a few little Euphyllia so I was ready to pull them out if needed. I didn't have a huge investment in them either, so the risk was a little more acceptable.
So, armed with a bit of peppermint shrimp research, I went to the local store and looked closely at their stock to be sure it was the right variety. As far as I could tell, they were. So I brought back four of them as a test with a plan to buy more if they did their job.
There was no need for more. Those four shrimp went to work immediately and destroyed the aiptaisia infestation within two weeks. Even better, to this day, they have never attacked a coral in this tank. (knocks on wood)
Every so often a single aiptasia will grow and disappear as they find it. Curiously, all but one. There's a single aiptasia they won't touch and I don't know why.
Picking a Peppermint Shrimp
If you're dealing with an aiptasia infestation and want to give peppermint shrimp a try, I recommend familiarizing yourself with the different varieties.
When I went to the store to buy mine, I was trying to identify them with a printout in my hand. When asked by a store employee what I was doing, I told him I was trying to be sure I got the right one. He responded that "all peppermint shrimp are the same."
They are not. There are six major ones you'll come across. Only one or two will actually do the job.
According to this thread on Reef2Reef, Lysmata wurdemanni or "A" on the photo is a true peppermint shrimp. In the comments, someone also mentioned success with Lysmata boggessi or "D."
The only ones I found at my local store were Lysmata boggessi and they worked like a charm. These ones are also easy to spot as the only one with a black tail.
Still at lot of algae to eat but we had an urchin take care of that.
Other Natural Aiptasia Predators
Filefish and peppermint shrimp aren't your only options to beat aiptasia. The Copperband Butterfly and berghia nudi also work but come with their own difficulties. Namely, while the butterfly is beautiful, it can be hard to feed and attack inverts. The nudi on the other hand only eats aiptasia, meaning that once its job is done, it will starve.