What were you thinking about adding? Tell us about your pond. Length, width, depth, fish (how many, size, type) and what plant materials you have in it. Post pictures if you can. Also describe your filter system, if any. You are going to get a lot of ideas here, along with the likelihood of some free plants (except for postage, of course).
It is likely that you will have more snow and cold weather before "Spring". Are you in upstate NY, Manhattan, or LI?