True peppermint shrimps vs the knockoffs. If your peppermint shrimp aren't eating aiptasia then you were probably sold the wrong shrimp to begin with. There is only one known and proven to be an aptasia eater. Its only from the Atlantic and Caribbean, any others is only a 50/50 shot of working. The photo below shows the true peppermint shrimp Lysmata wurdemanni (A) first one in picture.
Large Pic at Bottom
Here is some additional information also... If you want to purchase a Peppermint Shrimp to take care of aiptasia in your tropical reef tank, make sure you are actually getting L. wurdemanni. Peppermint Shrimp (Lysmata wurdemanni) are common additions to marine aquaria as a result of their interesting behavior, sociability and their reputation for hunting aiptasia. They are also a reef-safe shrimp. Peppermint Shrimp are relatively inexpensive (usually less than $10 and considerably less if you buy more than one at a time) and readily available online or at the local fish store. Unfortunately, the so-called Peppermint Shrimp is often confused with several similar looking ornamental shrimp species, and this confusion can lead to major headaches, as these Peppermint Shrimp imposters are NOT reef safe. Here’s what you need to know about the real Peppermint Shrimp L. wurdemanni. Although the name Peppermint Shrimp is by far the most common name in the hobby for L. wurdemanni, you may see this shrimp called the Caribbean Cleaner Shrimp or the Candy Cane shrimp. L. wurdemanni is a crustacean belonging to the class Crustacea. It is also a cleaner shrimp, although it tends to spend more time scavenging in the aquarium rather than cleaning its tankmates. L. wurdemanni is an attractive, striped (sometimes called veined) shrimp seldom exceeding two inches in length. The body color can range from red to orange-yellow to opaque with longitudinal dark red stripes. Although frequently called a Caribbean Cleaner Shrimp, L. wurdemanni is found in the Atlantic as far north as New Jersey. More likely than seeing a Peppermint Shrimp for sale as a Caribbean Cleaner Shrimp or a Candy Cane shrimp, you will see other species of shrimp sold as Peppermint Shrimp. This is one reason it is so important to: Use the scientific name when ordering this shrimp, and Know how to tell the difference between L. wurdemanni and the closely related species often sold as L. wurdemanni. The most common L. wurdemanni imposters are Rhynchocinetes durbanensis, R. uritai and L. californica. Here is a brief description of each of the imposters: R. durbanensis ; Commonly known as the Camelback Shrimp, Camel Shrimp or Dancing Shrimp, R. durbanensis is from the Indo-Pacific and is NOT a cleaner shrimp. You may see it advertised as the Candy Shrimp or, of course, the Peppermint Shrimp. Sometimes it is also called the Hinged-Beak Shrimp, referring to its hinged beak or rostrum. R. durbanensis is patterned with red and white stripes (similar to some specimens of the species L. wurdemanni), but this ornamental shrimp is not reef-safe like the true Peppermint Shrimp, which will seldom harass any corals or anemones beyond aiptasia. R. durbanensis will eat aiptasia, but it may very well eat your soft corals also. This shrimp can be easily identified by the obvious ;camel hump; on its back. R. uritai ; Commonly called the Camel Shrimp or Camelback Shrimp, like R. durbanensis, R. uritai is an Indo-Pacific shrimp and is also NOT cleaner shrimp. While very similar to R. durbanensis, R. uritai does not have the same pronounced beak and white streaking that R. durbanensis has. In addition, the coloration of R. uritai is somewhat duller. Further, R. uritai, unlike R. durbanensis, is currently known to be native only to Japan and Korea. Finally, the beak on R. durbanensis has 9-10 teeth along the top, whereas R. uritai only has 7-8 teeth. Like R. durbanensis, R. uritai will eat aiptasia but may very well eat your soft corals too. L. californica ;Commonly called the Lined Shrimp, the Red Rock Shrimp or the Catalina Cleaner Shrimp, L. californica is from the Eastern Pacific along the southern coast of the United States. Although similar in appearance to L. wurdemanni, L. californica is a temperate species and, therefore, inappropriate for the tropical reef tank. If you want to purchase a Peppermint Shrimp to take care of aiptasia in your tropical reef tank, make sure you are actually getting L. wurdemanni.
And if you want to read some really technical info click this link.............http://decapoda.nhm.org/pdfs/27306/27306.pdf