One way to kill and get rid of prolific and pesky aiptasia sea anemones in a saltwater aquarium is by injecting them with any of the following chemical or liquid solutions. When using this method, for the best results you should inject the solution of choice directly into the stem of the anemone with a needle and syringe. If working with a caustic chemical, it is wise to wear protective eye goggles and gloves as a precaution.
Bottled Lemon Juice Concentrate
After some experimentation, we discovered this liquid gave immediate results. It is a reef tank safe, effective, and easy procedure that costs only pennies to perform. Just follow these simple instructions on how to eliminate aiptasia with lemon juice injections, which includes before and after comparison photos so you can visually see the results.
Injecting aiptasia with calcium hydroxide (kalkwasser) in a concentrated solution is one of the most common methods used. The consensus we get with this method is that it does work but is not very efficient unless done properly. The kill rate is low if the calcium hydroxide is not directly injected into it and if the solution is not strong enough. Another problem is that if you try to kill too many aiptasia at once, it can cause a problem with the pH level in your tank by adding too much CAOH2 at one time.
When using this chemical for injection, it can be mixed strong enough for a certain kill. Beware, there is a WARNING with this one. When mixed in a concentrated solution it can remove the skin from your hands or other body parts. Removing the rock from the tank and dribbling the sodium hydroxide solution over the anemone it gave 100% mortality rate. When having to get to an anemone that had its foot embedded in a crevice, the mortality rate was only about 50%. This was due to have to guess where to put the solution and if the target was not right on.