I was defrosting fish and forgot about it. It has been left out for a long time. How long can fish actually be left out before it goes bad?
A quote from the below link;
"Do not thaw frozen seafood at room temperature. Thaw in the refrigerator or defrost in the microwave oven. If thawing in the refrigerator, allow one to two hours per pound of seafood".
Another quote from the link below;
"... If food is allowed to remain at room temperature for two hours or longer, bacteria can multiply and cause food poisoning. - Even a tiny amount of contaminated food can cause severe illness. If you have any doubt about the safety of the food, throw it out!"
I know the fish is long eaten or thrown away by now, but since the question is still open I'll post.
Defrosting requirements of raw fish is a little different than that of land-mammal meat. I'm sure that the growth of bacteria for meat and fish is about the same, but fish will actually deteriorate faster than the meat even in the absence of bacteria if exposed to air.
I would cook and eat meat that's been left out raw up to 2-3 hours (depending on room temperature). However I would not eat a fish that's been left out in a warm room for much more than an hour of being defrosted. Fish decays faster than meat. It was my understanding that fish decays faster in air than in water (I was always told to always defrost fish in the sink rather than the counter), however I couldn't find adequate references to back that up (see comments). Whether in the sink or on the counter, bacteria will probably spread at just the same rate as any meat once the fish is defrosted so the clock is ticking.
According to the FDA, no longer than 2 hours, based on basic safety. My friend works for a top of the line restaurant in LA and they leave the raw fish at room temperature for up to 7 hours. She once told me that at culinary school the rule is no longer than 4. Even so, don't wait plan ahead and keep it fresh.