Over the past few years I've caught some hatchery fallbacks (post spawners) that fought just as hard as pre spawners. One hatchery fish I decided to keep and it wasn't until I was cleaning the fish that I found out it had already spawned. The fish was fairly bright and felt normal. Is there any other signs to look for to determine the status of the fish?
Mark

Look for skinny body and red fins.

In the past I have killed fish before thinking they were fresh later to find out that they had actually spawned but where still very bright. A very good way to check is to look at the bottom of their tail. If it looks all beat up they've probably been in the river a while and most likely have spawned.

Are you talking about a summer-run that has already spawned and has reconditioned its body? In this case the fish is chrome, fins have healed and, because it is actively feeding, dosen't have a sunken-in belly. I've caught a few of these on my namesake river in February. These have been hatchery hens that I thought were just bonus late winter brats. While cleaning them, they have immature eggs skeins, the size of a pencil. They also have poor quality flesh.
The only thing I've noticed is that they have an enlarged head, but only because the width of its back isn't proportioned to its head.

Skinny body and red-tinted fins is a good clue BUT I have been fooled by fish that lacked these characteristics. Even the bottom of the tail being ragged is not reliable, though another potential indicator.

Usually the fish will exhibit one or more of these signs but I have caught spawners that appeared perfect in every detail-even a firm belly only to have them "de-flate" inthe fish box an hour later.

The best sign I have found when I suspect a bright fish has spawned is I look at the bunghole. If it is "pooched" out or protruding, that usually means the fish has spawned or has loose eggs and would be poor quality anyway.

Sometimes, it really is hard to tell-even with a trained eye!