Which tuna sold for 2.5 million?

I'm intrigued by the mention of a tuna selling for an astonishing 2.5 million. Could you please elaborate on this? What specific type of tuna was it? Was it a record-breaking catch? Was there a particular auction or market where this sale took place? And most importantly, what factors contributed to such a high price tag? I'm eager to learn more about this remarkable sale and the world of high-end seafood auctions.