Crayfish

Crayfish were introduced with the Lumbridge and Draynor Diary on 14 July 2008. 30 Cooking experience will be gained upon successfully cooking a crayfish, which requires Level 1 Cooking. Eating a crayfish heals 20 Life Points. Players will completely stop burning this fish at level 29 Cooking.

It is obtained by fishing with a Crayfish cage, which can be obtained as a free sample from Hank's Fishing Shop in Lumbridge.

Trivia

 * The image of this fish has changed repeatedly. Between September-October 2009, it changed two times. They started as three small crayfish, were changed to a single small crayfish for about three weeks, then changed to a large one, similar to an upside-down lobster. It also once had a detailed icon of 3 detailed crayfish in the Grand Exchange database.
 * Real-world Crayfish are indeed related to the Lobster.