I fed mine if they acted hungry but I always used an easily digestible food. This site has feeding info: http://www.koifeeding.com/koi_feeding_winter_cold_water.html.

Also, you may want to check out the Pond forum (see link below).

Here is a link that might be useful: Pond Forum

40-45 is still pretty cold. 45-50 would be better. Are they active, coming up and begging for food - or huddled on the bottom hibernating. If the latter leave them be. Otherwise they can be fed very lightly a winter food every couple of days - make sure the food is moistened and not fed dry, otherwise it's like cement in their intestines. You can feed a few peas too t keep them from getting constipated. It sounds funny but fish can die if they get totally backed up -- it almost happened to one of my fish but eventually got him unplugged feeding peas and garlic. I thought they'd have the sense to stop eating if they weren't able to digest food but that's not the case!

thanks KASHKA and ANNZ, sounds like good advice. right now my fish are moving around, but that's about it. i've been feeding them a little 2-3 days a week with spring and fall food. peas and garlic uh? i'm not going to ask how you knew the fellow was constipated. tiny little bubbles? :-) i'll toss a little in next time just for ***** and grins (pun intended) thanks again.