I left a lively catfish in a big livewell overnight. Temp mid 50's.I'm pretty new to catfish fishing. I thought they were so tough it would make it through the night. This morning I went down and it was upside down and dead. The color had drained out of it's skin and it was stiff. I put it on ice. I wish I'd done that before but didn't have the ice then. Has it gone bad? Thanks