Hi Ryan, I believe they will surface feed in water as cold as 12C (~55F) though I think 17-18C is much more common. I also do not think Catfish are high on the list for Otter diets because of all they defense mechanisms they have. If your Koi survived them, Id bet the CHC are just fine.

Last edited by SethM; 03/31/20 01:11 PM.