Thawed out raw crayfish - is it safe to cook and eat after 3 days in the fridge?

I had a raw frozen crayfish which I had planned on cooking and eating on Christmas day. Unfortunately, this didn’t happen.

I thawed it out on the bench for about 30 minutes on the evening of the 25th and put it in the fridge when I realised none of us would have room in our stomachs to eat it.

It is now the early afternoon of the 28th and I am considering cooking it for lunch. Would this be safe?

I have never cooked one before and have reservations about seafood.