However the extreme conditions have taken their toll. The first sign that things weren't right today was a powerful smell as I approached the pond. It was not the normal 'fishy' smell associated with the area but much more pungent and not something I'd ever noticed before.
On closer inspection I found quite a number of dead fish scattered around the pond margins.
I'm no fisherman or fish expert but they looked like pond carp to me (I'm happy to be corrected on this) and it seemed as though all sizes had been affected.
I've read that the problem can be lack of oxygen but also if there has been snow on top of the ice (and there has here for quite an extended period) it won't allow sunlight into the pond.
Fish rely on some warmth in the water to maintain their metabolic rate, if the temperature dips for a long time and they have undigested food in their gut it can rot and create toxins that will poison them.
Dead fish need to be removed as soon as possible to stop further fish deaths from toxins being released into the already oxygen depleted water.
I do see the owner of this pond quite often and will ask if it's possible to do this.