Goldfish under ice

[John in Nelson]

Hello Pond People,

I'm baffled, today, I saw a few goldfish under a sheet of ice in only 4" of water, must have frozen solid this winter (I'm in British Columbia, 1 hour from the USA border) yet the fish were swimming around . .definitely no sign whatsoever of fresh water entering this little pond at a hotel, almost stagnant and no fountain.

I have a 30 ft dia. pond and go to great lengths to keep a fountain / bubbler going all winter long (even with -18C !!) believing my 50+ goldfish need oxygen to stay alive during the 5 months they are under the ice and snow. Pond is 31/2 ft deep. Please 'someone' help me as to what goldfish actually require to survive the winter. Seeing a few goldfish today in 4" of water with an ice layer baffled me, knowing the pond this little hotel pond must of been frozen solid less than a few weeks ago !!
Email:(e-mail address removed)
THANKS !

 

[addy1]

goldfish are tough , no clue how they could do that

 

[mrsclem]

My lotus tank froze solid this winter and when it thawed I found frogs and tadpoles in there. Tough critters!

 

[HARO]

The ability of a goldfish to survive is inversely proportional to the money you paid for it. (Hey, I'll have to remember that one!) Seriously, though, the common goldfish is one tough little creature, whereas the fancier they get, the more likely you are to lose them. This is probably due in large part to the deformities foisted upon these fish through selective breeding. Remember also that cold water holds far more oxygen than warm water, and fish need less oxygen in their winter mode. Apparently there was enough in this shallow pond to keep these poor fish alive. By no means should anyone think that this example is good fishkeeping.
John

 

[shakaho]

I think a lot of the advice on winter pond care comes from the needs of koi, not goldfish. Koi are more sensitive to cold and heat than goldfish. Koi die readily from low oxygen levels.

Goldfish can survive in cold water with no oxygen whatsoever by acting like yeast and using anaerobic respiration.

There is then the caveat that fermentation as a strategy to survive anoxia is not restricted to microbes; goldfish (Carassius auratus) are a classic example. At 10°C, goldfish can survive complete anoxia for more than a week; the end products of metabolism are ethanol and CO2 (519), with the ethanol coming from a very standard yeast-type pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) reaction, with much higher activities of the latter, so that acetaldehyde (a cytotoxin) does not accumulate (536). The ethanol diffuses into the surrounding water.

from: http://mmbr.asm.org/content/76/2/444.full

There are many anecdotal reports of goldfish surviving completely enclosed in ice. As long as there is a film of water around the fish, this is possible, although probably rare. If the fish actually freezes, it will not survive.

In most of the northern states of the US, goldfish are a nuisance fish in natural lakes and ponds, even though these freeze with more than a foot of ice (without holes) and may have a heavy cover of snow over that. In spite of this, if I had a goldfish pond that froze over, I would keep a hole open. The fish might not require it, but they will benefit.

 

[addy1]

A fellow ponder here, around 7-8000 gallon pond, golfish only, aerator running all winter, hole open in the ice all winter, low stock load, ammonia zero, nitrates zero, nitrites zero, ph 7.9
anyways, he lost 95 percent of his fish. The ice melted and dead bodies started showing up. Pond bottom clean of muck and plant debris except dormant lilies. His filters are off, not sure what kind he uses in the summer.
He also has a small separate pond with goldfish, there too lost over 95% of his fish.

He asked me what I thought, tell the truth I have no ideas.

You wonderful pond people have any ideas? Lowest we dropped was around -10

 

[HARO]

If you find out what it was, Addy, please let us know. No idea what killed my koi. Only a lew cedar leaves and spruce needles on the bottom, and one dormant waterlily. I open a hole in the ice twice a week.
John

 

[addy1]

This guy had it always open. From big to tiny died, a few and I mean a few common orange gf made it.

I posted this info in its own thread if anybody has any ideas

https://www.gardenpondforum.com/thr...r-95-of-the-fish-are-dead-as-ice-melts.13754/