Stay away from the chocolate chip, they'll eat everything. The white sand stirring stars will eat all the life in your sand bed so you don't want one of those. Linkias live of film algae and need a lot fo rock and a tank at least a year old to survive. Stick with the serpent and brittle stars. I have one of each, the serpent is orange and the brittle is brownish/red. I spent 1.5 hours acclimating them with a drip. They hide mostly during the day but at night go around eating up whatever debris they find that's tasty. The serpent is new, so he still mostly hides, but they go around more in the light then the brittles do. They spend a lot of time in the same crack as my firefish spends the night in, they haven't eaten him yet, lol. I give them a small piece of scallop (1/3 the size of their central disc) each once a week to make sure they are being fed well enough. Very interesting critters, if you must have a star don't overlook them!