Today, i decided to move the ranchu into a new pond for the first this year. If i had any confidence in our weather improving soon, i would have kept the ranchu in the pond they were in for a little longer. However, last year saw freezing temperatures right through to the middle of March. This would make getting the spare fresh ponds water up to temperature with each water change quite a challenge, aswell as expensive. I'm also not sure im comfortable leaving them in the same water for several more weeks (totaling around 19 weeks!). The water quality has definately been deteriorating.
The pond that the ranchu have been moved into, has been aged for a couple of weeks, and i plan to hold off feeding the ranchu until i feel more confident temps and water changes can be carried out again regularly and relatively trouble free.