Tuna

Ironman verdict

5 monsters drop it. The easiest is Tyras guard (level 58, 3/128); the best rate is Chaos Elemental (level 305), at 1/12, about one every 2 kills. You can also make it yourself: it takes 30 Cooking and gives 100 Cooking XP, using Raw tuna. Other sources include Young impling, Gourmet impling, Young impling jar and Gourmet impling jar, plus 4 more listed below. Making ten takes 10 × Raw tuna and gives 1,000 Cooking XP. Reaching level 30 Cooking takes 13,363 XP in total; the Cooking calculator counts the actions and materials to any target, and the Cooking guide has the Ironman training route. 5 recipes use Tuna, including Attuned portent of restoration IV, Chopped tuna and Crest part (Caleb). Tuna is available on free-to-play worlds too. It is tradeable on normal accounts, but an Ironman cannot use the Grand Exchange or trade for it, so the sources on this page are the whole list. High Alchemy turns one into 72 coins, which is 48 less than the shop price, so buying it to alch does not pay.