Thanks for the advice - we took him off the bloodworm as we had our suspicions that may have been the cause!
He is only a small fish so nowhere near a foot long. We are moving house soon and we have promised him a brand new tank and all accessories so perhaps he can fulfil his potential then ;)...
Frank my fantastic 5 year old Shubunkin is not happy :(
He is sitting on the bottom of the tank alot and only seems active for short times during the day and evening.
A couple of weeks ago we noticed a build up of waste which seemed to be red in colour and almost have a mouldy-like covering...