Alright, I'm going to bug all you pond sleuths a bit more.......as I still have many questions, and I'm getting mixed answers from websites and well meaning people here in town.

1. My pond is 250 gallons. It's 3 feet in the deepest spot, and is right next to the house. I have a floating "stock tank" style de-icer (safe for plastic) made by Farm Innovators, Inc. It's the blue one. Will this be enough or should I get a submersible? Winters here have been KNOWN to get to -20F, but that was like 15 years ago and not normal. There ARE below zero days though, every winter.

2. While preparing the pond for the winter, is it advisable or necessary to get rid of the fuzzy algae I have growing all over the liner? My pond seriously looks like it was made out of green "high traffic" carpet. The water is clear, but the sides are covered in it. I love the look, but now I worry that it could possibly turn into a rotting mess once it gets cold.

3. Is a large water change needed as a last preparation? Or is that risky?

4. I know to stop feeding once the water temp is at 50-55..... will the fish still be swimming all around and begging and stuff?

5. Water temp right now has been fluctuating between about 63 and 70, should I be feeding wheat germ? I just bought more regular food, not thinking about the wheat germ...... is it necessary?

Sorry guys, but I'm starting to get anxious about all this. I'm going to worry about those fish alllllllllll winter. I'm sure I'll have more questions, I just hope I'm not being a pest.

sorry i'm not sure about what to do because i don't have a pon myself but my dad does what he does is:
he does a big water clean
takes water params every week
when the forcast is for a very cold day, he gives the koi a big feed the night before, so they arn't as hungry
he does take the algae out but i'm not sure if you REALLY need too.

sorry about not knowing about the de-icer, it doesn't get that cold where he lives

Erika, here's my advice:

1. -20, that is very cold, might be a good idea if you can get another heater? If you can’t I’m sure (strong) fish will be okay.

2. Don’t worry about the algae, it'll die back in winter by it's self, and the fish will graze on it if they are hungry.

3. I do a water change before winter and I also medicate - like a general tonic, just for the extra bit of protection before winter. And I do it again in spring as soon as temp are constantly above 10C.

4 & 5. When temps get down to about 15C I just lessen the amount of food they have and when down to 10/12C (during the day) I switch to wheat germ, then when below 5/6C I stop feeding, on mild days in winter you give them a bit of wheat germ or small about of brown bread. If they beg for food - you'll just have to be vigilant.

Also, during the summer I feed mine at about 5 or 6pm, as it is to hot during the day for them, but autumn/winter/spring (pretty much when I switch to wheat germ after day lights saving) I feed at midday/lunchtime as their digestion is better then and it is still light.

Okay, thanks Loz! So when you're saying your temps, are you referring to water or air temp? I've already cut back feeding to once a day, but it's been with regular food. Looks like I need some of the cool water food, eh? I'm just going to be really weird about stopping their feeding, it's going to be so hard, especially if they're still out swimming around!!!

I think I'm going to get a submersible, just so that I can feel a bit better about it all. Does anyone else use aeration? Some have told me that it's important.

Im a bit worried about your pond being 3 foot deep. It sounds like you have the same kind of winters as me. For fish to successfully winter through I reckon 3.5 to 4 foot may be needed. I know you have the deicer but will it be enough, i dont know.
Just make sure you are extra vigilent for frosty days I suppose. Do you have anything in case of emergencies to move them to? I only have a 34 gallon ready, and that will take two at the most.

Im going to chance my lot without any heating but will get a de icer for the coldest of days.

Im going by water temps. Keep feeding normal food until it hits 10c then wheatgerm until it gets to 5c and only feed late morning.

My fish for some reason think its spring. They are all chasing one fantail which is getting heavier and heavier so maybe carrying eggs. Im a bit worried she might not make it through a winter with eggs inside her.

Oh, and ive got crocuses appearing which i thought were spring plants.

water temps

it was hard last year to stop feeding... but i managed...

i use an air pump in summer, but turn it of for winter.

THanks guys.......

Sandy, the pond sits next to the foundation of the house, so I'm thinking (hoping) that the heat from the crawlspace on the other side of the foundation will help keep it warm. The husband seems to think it will. There's also a "hot spot" there that we still don't understand.... we'll find it dug up, and the rabbits, birds, and squirrels will be seen sitting in the hole. Snow instantly melts there too. It's kind of strange, but since the pond is there now, I hope it helps keep it warm.

I would worry that your heater is isn't going to handle that cold of weather. You may be good with two heaters? I don't know. I do know that I have the same kind of stock heater and when it didn't get above 20 degrees here for two weeks it only kept the area it was at from freezing. I had about 3 inches of ice on top of the pond. My pond was larger, 4,000 gallons and almost 5 feet deep, so it's not going to freeze solid. Yours might freeze solid with just the stock heater. I would suggest bringing the fish in this winter and keep the heater in the pond to see how it works out. If all goes well keep them out next winter.