Melt butter in a medium saucepan over medium-high heat. Add fennel; cook, stirring constantly, 2 minutes. Add rice; cook, uncovered, 2 minutes, stirring occasionally. Add chicken broth, water, and wine; bring to a boil. Cover, reduce heat, and simmer 10 minutes, stirring occasionally. Add crawfish; simmer, covered, 15 additional minutes or until liquid is absorbed and rice is tender, stirring occasionally. Stir in peas and cheese; let stand 5 minutes.