Your pan isn't hot enough.

Probably. That’s the number one reason tuna sticks. Second is moisture.

Tuna needs high, high heat to sear properly. If the pan isn’t screaming hot, the surface won’t cook fast enough to release from the metal. Put your pan over medium-high to high heat for a solid two minutes before adding oil. The oil should shimmer, not smoke (unless you’re using avocado oil, then smoke is fine).

Also: pat your tuna absolutely bone-dry with paper towels. Any moisture turns to steam and creates a barrier between the fish and the pan. That steam keeps the tuna from browning and glues it to the surface.

Use a thin oil with a high smoke point — canola, grapeseed, or avocado. Olive oil will burn and taste bitter. And once the tuna hits the pan, leave it alone for at least 90 seconds. Don’t poke or slide it. When it’s ready, it’ll release on its own.

A screaming hot pan and dry fish are non-negotiable.