Keith,

I think your observations and not seeing any dead fish in the river may be a testament to you and your friend's fish handling skill. Steelhead are hardy, within reason. You might pay a little closer attention to water temperature. I don't have enough information to be conclusive, but I think you're pretty safe up to 68 degrees F. Beyond that, I'm not certain. I've personally had some bad experience not being able to revive trout in 72 degree water, so I stopped fishing.

Sincerely,

Salmo g.