How long can my pond be iced over before the fish are in danger?

[koikeepr]

Right Strop. We care for these fish like dogs and cats--they become like part of the family, so we as their human caretakers worry about 'em all the time. Checking on them like they are children.

You may lose some fry due to the cold, but that would just be normal selection in nature. Nothing you can do...you will see come spring.

 

[rdk]

The ice this morning is advancing toward the air pump hose. Should I increase the rate of air flow on the air pump or should I leave it alone? RDK

 

[charrold]

From my (albeit limited) experimentation with the air-stone deicing so far I have several observations:

1 - Do not put the stone all the way in the bottom of the pond - keep it near the top since you are just trying to prevent ice over and add a little oxygen (mine is about 1/3 - 1/4 of the ponds depth). Too much deeper and it can cause the water temp to go too low in the lower depths of the pond. In summer put it down low to oxygenate the deep layers and promote mixing of warmer water into the bottom layers of the pond.

2 - No bubbler, no matter how strong, will stop your pond from icing if it is cold enough. With wind-chill last week it was below -10 for over 48 hours and got as low as -28 for a good stretch. The longest I kept a hole in the ice was about 2 hours and required many buckets of hot water. If you look back though through the thread you will see this is OK since the depletion of oxygen is not immediate and the fish will be alright for a couple of days to many weeks depending on fish load.

3 - In spite of the extreme cold of the last week my little air pump runs like a champ which means even when fully frozen over I am adding oxygen to the waster since it is still bubbling in there. Also this creates some really cool "ice bubble" effects on the pond's surface that look cool in different light.

4 - The fish are fine even when you can't see them. I miss them very much, but they are in there and they will be taking over all my free time again very soon :biggrin:

Enjoy the break from constant care of your fish and plan your spring pond improvements - it will be here before we know it!

 

[koiguy1969]

i read about but havent tried this, but it kind of makes sense... let your pond freeze over with a nice thick layer of ice with a small hole as usual then simply pump out a couple inches of water. this creates an insulatory air barrier between the ice and the water and still allows for waters surface to be broken for gas exchange even if the hole should freeze up for any reason.

 

[rdk]

Charrold Are you saying If my pond freezes over and I have my air pump. pumping air under the ice I do not have to worry about making a hole in the ice?

 

[charrold]

RDK, In theory at least you would need some sort of hole eventually as the small barrier between the ice and water would eventually become itself saturated with gases and the exchange would stop at some point. I would think however that time frame would be much longer than in a situation where the ice was directly on the water's surface. And since you are continuously pumping oxygen into the water even in the event there is no hole the time frame will extend significantly regardless of the air/water/ice gap.

As my pond is significantly smaller than koikeepers or koiguy's ponds my concern is that my time frame regardless of the exchange rates or gaps or whatever else happens is significantly shorter since I have such a vastly smaller water capacity and therefore much smaller oxygen content. (RDK - It sounds like our ponds are actually roughly the same dimensions and I came up with about 750 gallons roughly in my pond and my fish load is pretty high as well as the decaying plant matter - I got a lot of it, but I know there is still some in there which will add to the CO2 content.) If my math was right based on some of the links posted earlier then I have between 3 and 5 days before the CO2 rises to a level that will start to suffocate the fish if there is no exchange (ie no hole somewhere). Koiguy - I bet you would probably have at least a week and a half or more before it became a problem and would likely be a non-issue since the ice would melt off enough to have a hole in that time so the small amount of time of not having a hole is probably OK for you.

It isn't oxygen in that is the huge problem it is the CO2 concentration that will eventually cause the fish to die. Without a hole eventually the air and water under the ice will become saturated with CO2 and that will be the end of the fish :biggrin:. Water and air both have saturation points (although it is MUCH higher for air than water) and once reached the oxygen you pump in will no longer be absorbed into the water no matter what without a way for the CO2 to escape and allow the O2 to replace it.

 

[koikeepr]

right, you're not putting the air stone in for oxygen, you are putting it in there to maintain a small hole open so that there can be gas exchange.

 

[koiguy1969]

well it just isnt an issue for me anyways.. i have an 800 gal pond in my basement that my fish winter in...but yes it would definately be beneficial to maintain the hole in the ice with or without the gap between the ice and water..... but this is the second year for leaving small fish in the pond with no aeration or anything...i'll let you know what happens in the spring. they all came thru trouble free last year. either way i wish you the best of luck guys.

 

[chilligirl]

Well, last week our temps dropped down to -5 C (23F), and with the wind chill, I wound up with a thick (3/4") layer of ice on the whole pond. Thawed a hole out in one corner, and stuck a 400W aquarium heater I had but wasn't using in that corner, along with a small bubbler at the surface, to keep the hole open. Then built a pond cover out of PVC and heavy poly.

The aquarium heater is doing a bang-up job of keeping the corner ice free - it actually heats that little corner to around 65F. And the pond cover, along with a slight warming up, has allowed the rest of the ice to thaw.

Right now it's snowing and around -1C/30F. Pond is sitting at 40F and is ice free

I'm optimistic about my pond wintering well. The climate is pretty mild here - it does get cold, but our super cold days are pretty limited. I was still feeding my fish right up until a month ago. And when I put the cover on, I had to cut down a ton of new growth on my canna (it doesn't seem to realize it's winter lol). I also saw that my marsh marigold was sending up a bunch of new buds, and my loosestrife was taking off. Plus my crinum lily had a flower bud on it.

Hopefully the pond will be back above 50 degrees by mid February and all my fish will have made it through

 

[koidance]

I have had many ponds in many houses,but I learnt the hard way,you must keep the ponds covered in Winter (in the UK anyway) this is why we only have raised ponds now,which I admit isn't going to help all those with ground level ponds,but the principle is the same.
Heat rises,so by >
1)adding a layer of thick Bubble wrap cut into strips and if you can stick them together.....
2)lay this on the 2inches x 2inches frames already made.
3)then completely cover with a white tarpaulin..
4)Fix cleats or hooks or nails all around the (lower) walls of raised ponds.
5)Then buy an inner tube from any old garage for £2 (not perfect ones) cut the tube into strips so you have strong elastic bands.Thread these through the individual holes that are ready made in the tarpualins.
6)stretch them down to meet the cleats or hooks and ,voila, a pefect tight fit.
.................................................................................................................................
If you haven't got frames,you can still use 2 x 2 long pieces of wood (very cheap to buy) and just lay this across your pond,put the buuble on this and the tarpaulin on top,you can use tent hooks in to the surrounding ground to tie the tarpaulin too.Don't worry about air getting in,it will around the edges.
........................................................................................................................
Type in "white tarpaulins on google" and the firm comes up top.Mine were so cheap,they are very strong with excellent penetration for daylight.Delivered next day to ordering.The thick bubblewrap can be left on the actual surface of the water but only two thirds must be covered,it won't sink it just floats.I prefer the bubble on frames.

The heat must stay in the pond -- you don't want to heat the surrounding air...I like white tarps as we have plants (watercress,starwort etc) covering the pond surface,and I do not want to lose them as the Koi eat them..

Here is a pic of my ponds in Summer >

you may be able to see some cleats in the walls.

 

[chilligirl]

love this idea - any pics of your ponds in the winter?

So, do your water plants survive over the winter? My cat's tongue (silvina?) was still going strong, but I scooped it all out, worried it would die and muck up the pond. My water violet and parrot's feather are still floating in there and look okay...

 

[koidance]

Hi,nice to "meet" another lady.......yes the plants survive,I love to see the fish weaving in and out of the stems,we allow half the surface covered but I cut back severely in the Summer - so it is a wonder they survive.I always favour watercress as it is the best plant to look after the water.It purifies it,and keeps the fish happy.We also have pennywort,starwort,water soldiers (funny plants they sink to the bottom then come back up in the Spring,fairywort,although the latter does die back in the Winter,but recovers in the Spring.The picture is showing the watercress just as it came into flower,but it was cut back the following week.
I will try and find some more photos,but I will take some when I can on the ponds under wraps.
Today the water in the Koi pond was 16degrees,so they were happy as Larry and eating well.The mixed pond was holding steady at 13 degrees,but I gave them a light meal of flake and some goldfish pellets.I was surpised to see so many fish come for food.Even the Japanese Koi came looking,also all the Sarasas & shubunkins and I glimpsed one of the Orfe.
I keep the waterfall running slowly in the mixed pond as the Orfe like it,here is a photo in Summer of my waterfall,the birds peck all the plants off then I have to replant it.

Our heaters are 300 watt,they are on all the time now.

 

[DrDave]

You might want to share whether you are in degress C or F since only a few members are actually in metric land. 16 or 13 degrees means nothing to me.

 

[chilligirl]

koidance - are your ponds heated? 13 and 16 seems pretty warm for this time of year. What zone are you in? Beautiful pond pic btw :biggrin:

 

[oldmarine]

Almost thirty years ago before I knew anything about carp and fish ponds, we had a 150 gallon pond with cheap feeder goldfish freeze and incapsulate the fish in a small unfrozen part of the center. Thinking that they were going to be dead, I didn't do anything. When the ice thawed out enough to where I could see the goldfish, they were just fine. Carp in general are quite hardy, and can tolerate some extreme weather changes. It's quick changes in temps that will stress the fish.