Question
Hi Robyn. First question is: do goldfish and frogs work together in a small pond (about 8 feet long by 2-3 feet wide by 4 -6 feet deep)?

And second question: What depth should I go to with keeping these animals alive during winter cold? The average temperature is about -6 degrees Celcius with short term lows around -16 to -20 Celcius. An extremely cold snap could get to -28 Celcius but that's very rare.

Do goldfish and frogs require an ice free surface? Do they have sunlight requirements? I'd rather not increase electricity consumption with a heater if possible. I thought about putting plywood over it to help insulate but this would reduce oxygenation/sunlight exposure. So would ice for that matter I suppose.

3rd question: Do frogs/fish prefer lots of shade directly over the water (maybe 60 to 80 percent coverage with some pond lilies) or would tall grasses, etc around the pond be enough for them with a few pond lilies? The sun is hot and directly overhead the pond in the dog days of summer.

Thanks for your time and help! Paul

Answer
The pond is not that small, almost 500 gallons with the smaller size estimate.  Goldfish will do fine with most species of pond frog.  Larger pond frogs like bullfrogs may eat smaller goldfish.  In turn, goldfish will eat frog eggs and smaller tadpoles.  I suggest setting up a tub pond in which the frogs can breed.  I then remove the tadpoles to my larger pond in the fall before the tub pond freezes.

Your temperature range is similar to what is found in Zone 5 or 6 in the USA.  It's not likely that you would get more than a foot of ice but could get that much.  With aeration, de-icers, etc., you can keep part of the pond open.  I would make your pond at least 3 feet deep, preferably 4 feet for your area.  If you want to make it deeper, that's fine.  Deeper ponds are harder to clean of course and may not have enough oxygen on the bottom so an air stone down there may be needed.

My page on winterizing ponds is at http://www.fishpondinfo.com/winter.htm

Goldfish and frogs can survive in an iced-over pond as long as there is an opening for gas exchange.  If the pond gets ice and then snow, that will block out light.  The fish can survive that for a while.  The darkness may kill off some algae though which help filter the water and provide food in the colder months (as well as the warmer ones).  When I get snow over ice, I use the net to brush the snow aside in a spot to let more light down into the water.  My winterizing page has ideas for keeping holes in the ice.  De-icers are heaters but they only come on when it's below freezing.  They can be expensive but work the best in really cold weather.

Frogs and fish both prefer shaded areas as much for security from predators (or perceived predators) as for temperature control.  Grasses around the pond may not be enough.  With new ponds, there's not going to be as much plant coverage at first which is fine but expect algae to take advantage of that.  After a few years, you may be tossing plants over the hill like I do!  If I didn't, there'd be no open water surface.  Good luck!

Robyn