What is the most expensive fish to sell in Sea of Thieves?

Could you please clarify for me what is the most expensive fish that can be sold in the game Sea of Thieves? I'm curious to know which fish holds the highest value on the market and what factors contribute to its high price. Is it a rare species that's difficult to catch, or does it have a unique use or feature that sets it apart from other fish? Additionally, do players need any special equipment or skills to successfully catch this fish? I'd appreciate your insights on this topic.