Plot idea provided by FTAnt!
"Okay Happy, I challenge you to a fishing contest!" Natsu said, pointing towards his little buddy. "You're on! Whoever catches the most fishies will have dinner bought for them by the loser for a week!" As Natsu cackled crazily Lucy rolled her eyes and asked Levy is she still needed help on that job she was doing at the library.
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Natsu and Happy had agreed to go to separate areas so the loser couldn't claim the other stole their fish. Mid-way through the day, Natsu wiped his brow and looked at the pile of growing fish he had "No way is Happy going to beat me!" he exclaimed to the woods. The fish were really biting and Natsu was sure he would be the winner. As the sun was setting, Gildarts, Wendy and Carla came to tally up all the fish. "Forty-nine, not bad Natsu." Gildarts said.
Natsu tossed the last one onto the wagon they had brought for his fish and grinned, saying "Let's go check on Happy." As they rounded the corner, everyone's jaw hit the floor. Happy was standing beside a pile of fish that looked like it could easily be triple what Natsu caught. In fact, it was. As Happy threw his last fish onto the wagon, Gildarts said "That's one hundred fifty-two. Happy is the clear winner here." Natsu passed out as Happy shouted gleefully, "Yay, Natsu has to buy me even more fishies for supper!"
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Later at the guild as Natsu was ordering the Happy's list of food he wanted, Happy said "I'll be right back." His pink-haired friend didn't really notice him leaving, he was too busy sulking and being comforted Lucy, who was trying to keep from laughing at the expression on Natsu's face. Happy went to the back of the guild, making sure no one followed him.
Suddenly a voice came from the shadows, "Well, do you have it?" "Yep. Here you go Juvia and thanks for the help in catching all those fishies!" Juvia sighed and said "Anything for such amazing shots of my darling Gray!" Juvia looked at the aerial pictures Happy had brought for her, the little blue Exceed making his way to the front of the guild as she did so. She sighed and clasped them to her chest, happiness filling her as she thought of all the new things she could design with these new angles to work with.
FTAnt's Idea: So it goes, Happy and Natsu get into a fishing contest with each other. Happy shockingly wins by a landslide. Afterwards, it's revealed that Happy enlisted the help of Juvia, and for her payment she gets something Gray related, like pictures from the aerial view, or some of his clothes that he's stripped off and lost during missions.