LOL - this just happened to me - my son left the freezer door open. The Larrys Reef food was defrosted. I re-froze it - and fed it with no ill effects. I'm not recommending that - but given the cost - I do not think its an issue. On the other hand - if it seriously smells bad, etc - then - perhaps not. But - look at sharks eating dead whales for weeks. etc etc. I would highly doubt there would be a problem (and for me there was not) - I believe it was thawed for about 24 hoursMy fridge went bad for 24 hours. All the frozen food melted. Temp was still cold, but not frozen cold. Now the fridge is working again but I wonder if I should feed my fish those food?