Sorry for all your losses diyguy! Did you use a heater/deicer?
I don't have fish, but I lost about 4-5 frogs, which was pretty unusual.

I didn't lose anything that I noticed, but it was a bad winter for us here in MS. We rarely ever get more than 1 dusting of snow a year and this year we had 3 snows, 2 of which were 5 inches or more.

We moved into our new house here in ontario in November. There was no snow yet but according to the previous owner, it was already cold enough to stop feeding the koi. The pond has been in place for probably 10-12 years and two of the fish were originals. We are new to being a pond owner so we did nothing. There was no heater but we were told to make an air hole and everything should be ok. When spring finally rolled around and the ice started to thaw we found all 10 koi dead!
Still not sure if it was winter or other factors because we also found a garden nozzle, a screwdriver, and about a foot of sludge. Needless to say, we have since started over, drained the pond completely (twice) and introduced 3 comets, 3 shubunkins, 2 koi and 3 feeder goldfish (originally 10 but 7 died).
Things finally seem to be going well and our fish seem happy :)

Hi
09 was the worst winter for my pond since 82. I kept tropical fish and had a COMPLETE wipe out . Not sure why has it has been colder in the past but the daytime temps
set several record lows. Stayed below 45 for almost 48 hours. Wiped out most of the tropical aquarium type plants but several did recover. 10 would have been a disaster also but had only goldfish and only the plants that survived 09. I was surpised that the goldfish made it through the long hot summer which is the reason I kept tropicals in the first place.lol. Has already been in the mid 90's and summer hasn't even started yet. Oh well about all you can do is keep trying??? gary

catherinet,
Yes, I use a pond deicer. My pond has a waterfall grotto and I built an insulated floating deicer box with large vent holes I mount in the grotto during winter. I install the pond deicer floating inside the box to keep a protected open area. There is a 1,700 gph pump located on the bottom of the pond directly below the heater and the pump shoots straight up towards the surface. This normally keeps a nice open area on the 36' deep end.
This winter MinnySnowTa had nearly 8 FEET of snow which started in early November and lasted til mid/late April. There were several extended periods where the HIGH for the day never made it out of negative temps. With all the snow I had a 5' high snow drift where my pond was and I kept digging out the end where I try and keep open water. In mid/late March we had a few days that hit 40� so I drug the hose out, used a 17# demo bar to bust open more ice and did a partial water change. At that time I found several of my large prize koi bodies but saw at least one smaller koi moving so thought there might be hope.
By the time weather warmed up enough I could start digging and busting up more ice I found I had NO string algea growing and no living fish. The snow was to deep to allow any light to penetrate to allow the algae to grow. In the Winter the algae is our friend, CO2 absorbtion, oxygen generation, food if needed. No algae, no fish.
Also considerable ice damage to rockwork, lighting etc. All repaired now and ready to add more koi.
I'm not sure if ponding qualifies as masocistic or not?
JJ

@DIYGUY,

I wonder if your breaking the ice contributed to the demise of your fish? I have been cautioned to avoid 'breaking' the ice with force as the water amplifies the shockwave and can kill them. Similar to fishing with dynamite. It's not the actual explosion that kills them, but rather the shockwave.

Sorry for your loss. Stinks when the fish don't make it.

My 4 comets died. 2 of them were over 5 years old. They had lived through 4 previous winters with the same set-up.

I kept 4 fish and 2 frogs in my 200 gallon pond, 2nd winter for them her in NY and I thought last year was bad! I did loose my air pump but found it after a day when the hole iced over. Other then that all I did for them was shovel the snow off the ice.

Everyone made it fine until I fed the fish too early. Everyone had to then go inside and warm up, and all was well again.

I can't believe how big my froggie is!

Sorry about your fish loss DIY pond guy.

I have to agree with groundbeef here,
if you did pound the ice, it was most
likely the shock waves that killed your fish.

The safest way to open the ice, is to pour
boilng water over the ice until an opening
appears.