I have 2 of them. They are great. Like someone else said they rarely move once they are attached. Both mine stayed where I put them. They do like to be where a rock meets the sand, as they usually attatch just under the rock. They dont get too big so a 10g would be fine in my opinion. They are not as demanding as other nems as far as lighting and water quality and they come in a variety of colors. They dont host clowns, but they do host anemone crabs and shrimp. I have anemone crabs paired up with mine. I feed them about 2 times per week and they look very healthy. Their stings are not very strong either so your fish should be pretty safe unless they dove right into it. lol.