Have you checked your water parameters? The fact that it's a new pond and you're starting to experience problems may suggest that your biological filter is not yet established. Use a really good water testing kit (the cheaper 'stick' ones are a total waste of time) and ensure, in the first instance, that the ammonia and nitrite are nothing higher than zero.
A slimy coat usually suggests that the fish is stressed (younger/smaller fish will be the first to show the signs) and the first thing to check out is the water quality, especially in a new pond. Also, unless your pond is particularly large, it may be overstocked, with the immature biological filter unable to cope.
If you find that the ammonia and/or nitrite are higher than zero, buy something like Interpet's Bio-Start (good bacteria) and put as much in your pond or filter as possible. Don't feed anything at all, which shouldn't be an issue at this time of year anyway.
If your water quality is the cause, it will take some weeks for the biological filter to mature enough to cope with the fish waste and ensure your fish aren't swimming in 'poison'.
If you're absolutely sure that the ammonia and nitrite are zero, a skin scrape may help, although most chemical treatments don't work once the water temperature has dropped below a certain level.
Good luck!
Posted on Jan 1, 2007, 3:01 PM from IP address 195.93.21.70