The Carpet Anemone, A Difficult Keeper
If you're considering adding a Carpet Anemone to your already established saltwater aquarium, one bit of good advice might be - “Don't”. If you insist however, at least be aware of some of the challenges or pitfalls that may await you if you introduce one of these beautiful animals into your tank. First of all, the Carpet Anemone is well named. Like a carpet, it covers a wide area. No matter what species of anemone you might consider placing in your aquarium, a rule of thumb is that an anemone can expand to a tremendous size and contract to a very small size indeed. It is the larger size that it may attain that you need to be aware of. A carpet anemone, which can at times measure up to three feet across, requires plenty of room. Lots more room than three feet, especially if you have already have other living things, most of which the carpet anemone will kill and eat, in your aquarium. The carpet anemone, besides requiring plenty of real estate to move around in, and it will move around, is not a very good neighbor.
The list of reasons not to keep a Carpet Anemone in a home aquarium is longer than the list of reasons for doing so. Besides being a poor neighbor as far as other sea life is concerned, and besides requiring a good deal of room, the Carpet Anemone also requires an environment in which the water is in constant motion. We're not talking about a gentle current here but something more like you would expect at the seashore where waves constantly pound the tidal pools. Put another way, a decent home for a Carpet Anemone can be a pricey proposition.
Lots Of Moving Water Is A Must - If you do have a very large aquarium system, a few hundred gallons at least, with a high turnover in water volume 30 times an hour is good, you're off to a good start. Other species of saltwater animals or fishes may be placed in the aquarium but, even though the Carpet Anemone usually enjoys a symbiotic relationship with the Clown fish, it can and usually will kill and eat anything that comes into contact with it. Other species of anemone usually do not do well in the same aquarium. At best, a Carpet Anemone and another species may kill one another, but the Carpet Anemone usually comes out the winner.
Carpet Anemone Species - There are several species of Carpet Anemone, the three main ones being (1) the Gigantic Carpet Anemone, Stichodactyla gigantea, perhaps the most difficult to care for, (2) Haddon's Carpet Anemone, Stichodactyla haddoni, easier to keep but has a venomous sting and an aggressive temperament (handle with care!), and (3) Merten's Carpet Sea Anemone, Stichodactyla mertensii. A fourth species, the Atlantic Carpet Anemone, is sometimes offered for sale. This anemone will eat any fish, including the Clown fish, that it comes into contact with and is a very strong stinger. There are other species of Carpet Anemone, but most are difficult if not impossible to maintain in captivity.
Other Bad Neighbors - There are several saltwater fish which you can keep in the same aquarium with a Carpet Anemone, which include some species of angelfish, trigger fish and puffers, plus crabs. The problem with these species is that while they may fall prey to the anemone, they also will very often take on the anemone and try to make a meal of it and the anemone very often is the loser in this case. So no matter how you choose to look at it, having a Carpet Anemone and almost any other species of saltwater life in the same aquarium is at best quite risky.
In summary, if you want a Carpet Anemone for your aquarium and won't take “Don't” as a piece of advice, at least find out all you can about the creature. In this case, knowledge is indeed power.