Well, not exactly a pond. I'm totally new to the fish scene, so please bear with me.

I would like to get a half-barrel sized 'pond' to start that I could use for a baby koi and put it outside on my patio. I live near the beach and the weather's been pretty cold lately (dropping to 45.F at night) So I'm worried that it would get *too* cold for a baby koi.

I'm sure it would be okay and all, just want to make sure before I go out and accidentally kill a sweet fish b/c of my stupidity.