This is the anemone shrimp from the Caribbean called the Spotted Cleaner Shrimp, Periclimenes yucatan. They are small multicolored spotted shrimp with moderately long wavy that spend most of their time perched on anemones waiting for fish to come by for cleanings. They are often part of big cleaning stations that may involve neon gobies, wrasses, and other cleaner shrimp such as banded coral shrimp and scarlet cleaner shrimp. They seem to prefer the condylactis anemones, carpet anemones, and ricordea, but are also found on just about any other kind of anemone found in Florida and the Caribbean. I dont know this, but I suspect that they will host with anemones from other oceans as well. Although these shrimp do like to nibble the ectoparasites off larger fish in the wild, they do not depend on them for their sole source of food and will easily thrive on almost any kind of food available to them. During feeding times they will actively swim to the surface and take food from your hand, so they are a lot of fun to care for once they get settled into your routine.
These shrimp never get more than about an inch long, so if you have fish such as triggerfish, groupers, wrasses, and snappers, they will probably get eaten so I would not recommend adding them to systems with that type of fish. Sea horses may also eat them, so I would not suggest mixing the two. They are reef safe and would be a great addition to any reef tank, especially a nano tank that has limited space.