Hi,
I'd recommend that you look for CU's that are >585hp and has either less than 80 80 cold/energy and MAX 45% poison.
Or a cu with 70 70 cold/energy , then you can probably keep it if it had less HP. 70 / 70 is hard to find.
With these stats of your current pet I think it'll be easier to sell if it had been black/white/red/pink.