Everytime I touch that track it turns into gold (Yes it turns to gold). Everybody knows I've got the magic in me (I got the magic, baby). When I hit the flow the girls come snappin' at me (They be snappin' baby).
When you buy a whole fish, less of the area that you're planning to eat is exposed to oxygen. This means it will keep a little longer. They estimate a whole fish will last a maximum of three days, while fillets will last closer to two days. Certain fish will dry out faster than others, the folks at The Lobster Place say, and some will change color slightly as they age.
So if it meets that criteria, go for it. Unlike shellfish, fin fish has a much longer life. You really don't have to cook it the day you bought it, but how long you have depends on when the fish market got it. So when I buy fish, I always ask how long I can keep it. Generally fin fish stays for 5-7 days after it was pulled out of the water. Given that it usually takes the fish market 2-3 days to get it, it leaves you another 2-3 days. This assumes ideal storage (at 32F).