In Hoot, why does Roy attempt to catch a mullet fish at the ending of the book?

The answer to the question of why Roy tries to catch a mullet fish is found in the Epilogue to Carl Hiaasen's novel, Hoot. 

Roy is at Beatrice's soccer game and is remembering his time with Mullet Fingers, also known as Napoleon Bridger Leep. He hasn't seen Mullet Fingers since the groundbreaking ceremony of the Mother Paula's restaurant. Roy goes looking for the mysterious boy, who was nicknamed Mullet Fingers by Beatrice for his ability...

The answer to the question of why Roy tries to catch a mullet fish is found in the Epilogue to Carl Hiaasen's novel, Hoot. 

Roy is at Beatrice's soccer game and is remembering his time with Mullet Fingers, also known as Napoleon Bridger Leep. He hasn't seen Mullet Fingers since the groundbreaking ceremony of the Mother Paula's restaurant. Roy goes looking for the mysterious boy, who was nicknamed Mullet Fingers by Beatrice for his ability to catch mullet fish with his bare hands. On page 291, it says,

For one thrilling moment he actually felt it in his grasp—as cool and slick and magical as mercury. He squeezed his fingers into fists, but the mullet easily jetted free, leaping once before it rejoined the fleeing school. Impossible, he thought, nobody could catch one of those darn things bare-handed, not even Beatrice's step-brother. It must have been a trick, or some clever illusion. 

After his failed attempt, Roy hears laughing in the mangroves. He calls out, asking if it is Mullet Fingers. He never sees the boy but finds a mullet fish in his shoe as he is leaving. He realizes catching a mullet bare-handed isn't impossible, and it wasn't an illusion. He laughs to himself and decides to come back the next day. He says "that's what a real Florida boy would do." In my opinion, Roy's decision to come back is made for two reasons. One, he hopes he will see Napoleon Bridger Leep again if he returns. Secondly, he is acclimating to his new home and desires to become a part of the Florida culture.