How do fish etc survive

[xyzzyplugh]

When the 'pond' is totally frozen over? What if it froze solid? would anything survive?

[j2buttonsw]

There is an amazing amount of dissolved oxygen in water for fish to survive in. If the pond had a layer of thick ice but was mostly water and you had photosynthesizing green aquatic plants as part of a balanced ecosystem then the plants would provide oxygen for the fish which would provide the carbon dioxide for the plants. Therefore, everything should survive for some period of time. If it were one block of ice then I expect only the micro-organisms would survive with the photosynthesizing ones existing the longest.

[WendyW]

The suggested depth for a pond is at least 18inches .. it is then very unlikely to freeze totally. Usually only the first couple of inches freeze over so providing it doesn't go on for too long then the fish are OK.

[wildwood]

The colder that water is, the more oxygen it holds. The temperature of the fish is about the same as that of the water. At lower temperatures the fish's metabolism slows down, so also uses less oxygen. It is most unlikely that the pond water would totally freeze solid, unless the water level is very shallow.

[Andromeda]

Actually, if a pond is totally frozen solid, the fish won't survive. There is only so much dissolved oxygen, and once that is depleted, it's goodbye fish. The length of time this takes will be variable, but isn't long. Photosynthesis is unlikely to take place much either due to a) an absence of a great deal of light and b) an absence of carbon dioxide to photosynthesize. This why fish pond owners are recommended to leave a small hole in the ice. You can get rubber rings and the like to ensure an opening is maintained so your fish don't suffocate.

Andy

[Andromeda]

Actually the above should have read "the pond totally frozen over" not "frozen solid". If a pond is frozen solid, it is unlikely that much in the way of higher acquatic life would survive, although certain algae and bacteria will.

Andy

[Jonathan R]

Not exactly an answer but.. One good way of keeping a hole in the ice is by using part-submerged plastic flowerpots (with the drainage holes becoming breathing holes). A ring of ice may form inside the pot but this can be removed in the morning by taking out and replacing the pot. Just remember never to crack the ice as the fish don't like it (like if someone taps on a fish tank), The best thing is to use boiling water in an old saucepan. Rest the pan on the ice and it will gently melt it. Just make sure you're there to stop it falling into the pond! If it did freeze completely, I wonder if the fish would become frozen in time like Buck Rogers?