Fish died from COld....How long before not eatable

[Annika Wallace]

We have a small system with two 250 gallon totes and a water trough.  All the fish in these are dead and very frozen feeling.  I want to know if you think or know if they are still ok to process  for the freezer.  Would like to know as soon as possible so can process as soon as possible.  These are blue tilapia

Annika