im not sure it might be the light or the pic itself but ive never seen a green aptasia they are almost always either brown,tan, or clear. that almost looks like a tiny bubble tip anemone
na man dont kill it it is a good anmomey if u have a clown fish it will go in 2 it. it will not hurt any thing in your tank. so if u want just kipe it i kept mine and my 2 fish love it her r some pic