if u position your tank away from central heating/fires/windows/direct sunlight you will have a more stable water temperature...

to be honest tho...once your little carp outgrow the tank ...which they will.....youll wish you set up with tropicals or marine.....

nearly everyone i know who has kept inigenous species has.....

plus when the fish are rehomed they will have extremely low resistance to natural water borne dieseases etc and will struggle to establish themselves in there new home

carp make a seriuos amount of waste matter .most of which isnt the crap you can see !!!!...you will be needing to do 1/3 water changes at least weekly when the fish become of a reasonale size and even more frequently when they get big