The eyes don't lie.

Look at the eyes first: clear, bright, bulging. Cloudy and sunken means it’s been sitting too long.

After the eyes, check the cut at the tail or belly. The flesh should be deep ruby red, not brown or muddy. The bloodline (the dark strip) should be a clean maroon, not grayish. Give it a gentle poke — it should bounce back, not hold a dent. And smell it: fresh tuna smells like the ocean, not like “fish”. If it smells fishy, it’s old.

Everything else — gills red, skin shiny, scales intact — matters, but eyes and flesh are the fastest shortcuts. A fishmonger who sells old tuna won’t fool you if you know those two.

Fresh tuna looks alive because it basically just was.