can i keep other shrimp with theese guys?
Harlequin Shrimp
Yes, since they only eat starfish. This makes them very difficult to keep alive in captivity.
I'm going to make a suggestion here, and you can choose to ignore it (and I may get pounded on by the regulars for even saying it). Take the next 6 - 8 weeks and stop shopping. Buy books and read them. After you've finished read them again. Stop looking at, thinking about, or making shopping lists of livestock, because quite frankly, you're not ready for this yet.
After your cool down period, go to liveaquaria and look at the section labeled SW Beginners. Pick one fish who's minimum size is 20 gallons. ONE FISH. Get that fish, either from LA or your LFS, whichever you prefer, get it acclimated in your tank. Stay like that. For 1 month, have just one fish in your tank. Keep it alive that whole time with no problem. If you manage it, go back to the SW Beginner section and pick one more, again, minimum 20 gallons.
There's a reason that these fish are in that section. They're easy to keep alive, give a lot of color and social interaction to your tank without any of the crazy nutritional needs that some of these creatures have.
Or, you can disregard this altogether, buy a harlequin, a moorish idol, an anemone, and a mandarin, and see how it goes! Choice is, of course, up to you - but for me, after many years of keeping saltwater tanks, I still very rarely even dip into the "moderate" care level fish.