1.4 Maple Syrup Density Measurement. 1.4.1 Background; 1.4.2 Hydrometers; 1.4.3 Hydrotherms; 1.4.4 Refractometers . 1.4.4.1 Optical Refractometers; 1.4.4.2 Digital Refractometers; 1.4.5 Temperature Correction; 1.4.6 Instrument Calibration . 1.4.6.1 Hydrometers; 1.4.6.2 Thermometers; 1.4.6.3 Refractometers; 1.4.7 Collecting a Representative Sample
Because of this distinction, you may safely use fish even after the sell by date has lapsed. If there is a use-buy date on fresh fish, then it is recommended to either cook or freeze the fish by that date. Commercially frozen fish, if kept frozen, can be safely stored for 10-12 months.
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).