Written for the Sterek Glompfest over on AO3 and tumblr for tx-toast, who prompted "Stiles & Derek being together but are different aquatic species."

Stiles nudged his way out of the hole he'd spent the night in. He had finally found a promising location at the base of an enormous coral reef that spanned nearly as far as the eye could see in the water, blocking off any paths further into the ocean. It was teeming with fish, and most importantly with crabs, and the reef would deter many of the bigger predators from deeper in the ocean from getting to this particular stretch of rocky sea-floor.

He had been too tired from a long day of swimming to do too much exploring yesterday when he arrived, but now the water was bright with morning sun and Stiles was more than ready to go try and meet the neighbors. He slithered the rest of the way out of his make-shift home and headed first for the reef to see if anyone already had a claim on the land.

Stiles hadn't been out for very long before he spotted one of the most beautiful fish-people he had ever seen making their way towards Stiles across the reef. Stiles stopped and waited for the person to catch up to him, and frankly to stare, because he had never seen a color like the person's tail, which seemed to shift between black, rich purple, deep blue, and even dark green as shadow and sun beams rippled across its surface. His tail fin was split into long, trailing lobes that Stiles wanted to suck.

He seemed to get even prettier as he got closer, and between that tail and those shoulders Stiles already knew he was going to have a hard time with the impending conversation.

The fish-person's approach had a distinctly predatory feel to it, and Stiles was just starting to feel uneasy when the man stopped a little ways away. "You're trespassing on our land," he called out to Stiles.

"Really?" Stiles looked back over his shoulder at the stretch of rocks, empty but for crab and shrimp and animal-fish.

The man's face looked a little pinched when Stiles swung back around to look at him. "We're close enough by that we consider it our own," he growled out.

"Okay," Stiles felt skeptical, "but does anyone actually use this area, or is it just, like, a buffer zone?"

The man's face twisted like he had just bitten into a toadfish. "I hunt here," he grumbled.

"Dude, I would so totally be way more than okay sharing with you." Stiles gave the man an up and down look.

"Don't call me dude," the man snapped.

"Then what can I call you?" Stiles grinned.

The man's face soured even further as he realized he'd basically forced himself to give out his name. "Derek," he spat.

"Great, let's start this whole conversation over again." Stiles swam closer to Derek, who didn't look all that pleased with this development, and stuck out his hand. "Hi Derek, I'm your new neighbor Stiles, and it's so great to meet you! This rock bed is way too big for one little eel to claim for their own, so please come by whenever to hunt like you usually would. There, now was that so hard?"

Derek was frowning down at Stiles hand like he expected an attack. After another second or so, when Stiles had been about to retract the offer of a handshake to spare everyone the angst, Derek shook his hand with a grip so ginger he might have thought Stiles was poisonous. Which, okay, Stiles will grant that that is not a bad instinct to have with eels, but Stiles was not poisonous in any way and would love to rub his entire body against Derek's the second he indicated he might appreciate something like that. Stiles had to admit his odds were not looking good on that front.

"Just stay away from the village," Derek growled.

"Okay," Stiles held up his hands, "I can do that, big guy, whatever makes you happy."

Derek nodded, his face smoothing out ever so slightly.

"Just, one thing I kinda need to know, but where is your village?"

Derek narrowed his eyes at him, and Stiles held up his hands again. "Hey, you can't say that's an unreasonable question. How am I supposed to avoid a place if I don't know where it is?"

Derek seemed to consider this for a long moment before spitting out, "It's on the other side of the kelp forest."

Stiles sent a sidelong glance toward Derek. "That's very far away for you to try to claim this area."

Derek scowled and Stiles found himself fighting down a smile at the sight. "Just don't let me catch you on the other side of the forest," Derek snapped.

"Sure thing."

"And I come by here every day, so I'll know if you try to cross."

"Every day, huh?" Stiles grinned. "I'm looking forward to that."

Derek's scowl deepened. "Stay on your side of the forest," he said before spinning around to continue on his way in a swirl of purple-blue scales and trailing fins.

Stiles had to hold in a sigh at the sight. "See you tomorrow, Derek!" Stiles called after Derek's retrieting tail. "It was so nice meeting you today!"

Sure, Stiles might have his work cut out for him, but someday he was going to get to touch those fins and his life would be complete.

Derek moved steadily along the edge of the reef, relishing the cool water and the quiet outside of the village. He kept an eye out for any flash of fins that would indicate an intruder or the long, pale-yellow-and-brown-spotted tail that would indicate Stiles. Not that Derek drew much of a line between the two, but so far Stiles had kept his word and kept to himself, so the sight of him was no longer cause for alarm. Which was good because he saw Stiles just about every time he went out on patrol these days.

Sure enough, he caught sight of Stiles in the rocky expanse at the edge of the kelp forest that Stiles seemed to favor. Derek frowned as Stiles slid out from behind a rock and darted over to him.

"Good morning, sunshine" Stiles grinned, "my heart sings at the sight of you."

Derek felt his frown deepen almost involuntarily. "Still haven't left yet?"

"Derek, how many times have I told you by now, I'm never going to find somewhere better than this? I'm settling down, my wayward fins have found their rock at last."

Derek huffed a gulp of water through his upper gills.

"What do you have so against me, anyways?" Stiles' smile was starting to look forced.

"You're an eel-person," Derek rolled his eyes, "I would have thought it was obvious."

Now Stiles looked offended. He drew himself up and crossed his arms, amber eyes flashing in the ripples of morning sun. "There is nothing wrong with being an eel, Derek, and frankly I wouldn't have thought you the type to stereotype like that."

Derek raised an eyebrow. "Are you trying to deny that I've had to chase off several eel-people trying to make dinner out of my neighbors?"

"Oh." Stiles uncrossed his arms and relaxed down in the water. "So this isn't because you think eel-people are faithless and lazy and good-for-nothing?"

"No." Derek's eyebrows climbed higher on his forehead. "This is because eel-people semi-regularly try to eat me or my friends."

"Oh," Stiles repeated. "Well," he continued after a moment of silence, "I can reassure you there, too. See these babies?" Stiles bared even, blunt teeth at Derek.

"Yes," Derek scooted back some, his own fangs starting to sharpen in response to the threat display.

"They're for crab, that's why they're blunt. So you don't have to worry about me terrorizing your fishy friends, unless you happen to be particularly close to the local crab and shellfish population."

Derek cocked his head, considering. "So, you don't eat fish?"

"Well, sometimes, yeah, you've gotta eat what you can get your jaws around, you know. But never fish-people, just the pure animals."

Derek hummed. "I still don't like you."

Stiles sighed. "Yeah, buddy, you've made that abundantly clear. But, not to worry, I've got plenty of time to change your mind."

Derek rolled his eyes and turned to continue his patrol.

"And Erica is already on my side, so you won't be able to hold out forever."

Derek whirled back around, barely keeping a snarl off his face. "How do you know Erica?"

Stiles' mouth dropped open (or rather, more open than usual). "Oh my god, who knew you could get even more beautiful?"

Derek snarled and flattened his fins from where he had flared them out in threat display. It took an effort of will to get his triggerfin to lay flat between his shoulder blades. "Stay away from Erica."

"You do remember that she does your patrol when you're off, don't you? Kind of hard for me to avoid her when she comes cruising through my patch of rocks."

"This is not your patch of - "

"And anyways," Stiles continued, loudly so as to drown out the end of Derek's sentence, "Erica and I and friends now, so she comes looking for me even when I don't see her first. So you see it's inevitable that eventually you will cave to my charms."

Derek growled and spun back around to continue his patrol.

"Great, glad we sorted that!" Stiles called after Derek's retreating tail. "See you tomorrow, sweetfins!"

Derek was tending to a particularly troublesome plant in his garden when he heard someone calling his name. He looked up, brushing sand off his hands, to find Allison floating at the edge of his garden.

"Allison," he greeted, swimming toward her.

"Hi Derek! I know it's your day off, but I was wondering if you would maybe come out looking for weeds with me? I'm out of all of my reds and golds and I've weaved as far as I can with the greens."

Derek hummed for a moment before deciding, "Sure, I could do with a swim."

"Great!" Allison's face creased with a grin as she clapped her hands. "Let me go get some bags and then we can go." Allison started to swim up towards the crevice she shared with Isaac before spinning back around to face Derek. "That is, if you're good to go right now? Which is totally no problem if you need to finish with your garden first."

"No, we can go ahead now, that's fine."

"Okay!" Allison dashed away again.

Derek went to get a cloth and scrub the rest of the sandy dirt and bits of weed off of his hands while he waited for Allison to return. She was back in short order with an armful of bags, all with her signature weaving style, and then they were swimming out towards the kelp forest together. Allison could have easily outpaced Derek on the way, but she kept her speed in check, silver-and-yellow tail flashing in the bright afternoon waters. Derek flared his fins and did a little roll once they were out in the open water away from the shadow of the reef, enjoying the feel of the sun on his scales. Allison was watching him with a smile tucked into the corner of her mouth when he came back around.

"What?" Derek frowned. "Don't act like you're not frolicking in the currents with Cora most every evening."

"I'm not judging you," Allison laughed. "You just seem so serious all the time - it surprises me whenever I see a different side of you is all."

"You make me sound like such a killjoy," Derek muttered.

"Sorry," Allison shrugged. "I guess we still haven't gotten to know each over very well."

"After you laid eyes on Isaac you weren't much interested in getting to know anyone else."

Allison snorted out another laugh. "Guilty as charged. Although Lydia tells me all the time that we're due to leave the honeymoon phase any day now."

"I wouldn't trust Lydia - she and Cora have been mated for, what, five years now and they've never left the honeymoon phase."

"Mm-hmm, seems like Cora's taking after her sister in that regard. When are you going to do the same, hm, Derek? I don't think I've ever heard so much as a rumor about you settling down with someone."

"And you probably won't,"Derek shrugged. "I've never been interested."

"Never?" Allison looked surprised. "I would swear I've heard Cora talk about an ex of yours before."

"Well," Derek sighed, "there was this one time I meet a sea-witch while I was out on patrol, and she made me think I was interested for a while."

"Oh, Derek, I'm so sorry." Allison turned to look at Derek with big, sympathetic eyes.

Derek shrugged again. "It happened. Now I know not to trust sea-witches."

They were almost to the kelp forest now, and Allison kept silent until they were nearly within its ever-moving shadows. "I'm sorry to have brought up old hurts. But, Derek, my old school used to deal with witches, and I learned a thing or two from them about how to resist their magicks. If you wanted, I could teach you sometime."

Derek cracked a small smile and took the olive branch for what it was. "I'd appreciate that, Allison. Now you get on with your gathering," Derek swept an arm towards the dim depths of the kelp forest, "I'll keep an eye out for anything unsavory."

"Thanks, Derek," Allison grinned and darted into the forest with a flick of her powerful tail.

Derek swam upwards a little ways to get a better vantage point as he settled in to keep watch. Allison could probably handle any predator that spotted her in the forest, but it never hurt anyone to get advanced warning of an attack. Derek ran his eyes over the rocky ground Stiles had claimed for his own next to the forest and idly wondered if he'd see Stiles today or whether Stiles would be busy hunting elsewhere. The only movement in the stones seemed to be crabs — Derek's fangs itched at the sight of them, but he kept his teeth firmly under wraps. He could go hunting on his own time. He ruffled his fins and turned to look out over the expanse of forest instead, hoping his gums would stop tingling away from the sight of his favorite food. It worked to a degree, but now that he knew he could easily go catch one, all he could think about was sinking his teeth into sweet, juicy crab meat and how good it would feel to file his fangs down on the hard, crunchy shell.

Eventually, Allison re-emerged at the edge of the forest, her head still down looking for weeds but her bags visibly packed with bundles of the stuff. Derek sighed in relief that she was almost done and took his attention off of his surroundings for a moment he immediately regretted when he caught movement out of the corner of his eye. He spun around, claws already out to meet whatever was approaching, only to relax when he saw it was Stiles streaking towards him.

He started to tense up again when Stiles showed no signs of slowing down, but Stiles didn't have claws out or teeth bared so Derek wasn't sure how to react. He turned to shout a warning to Allison, who was still laser focused on her foraging, only to get tackled from behind before he could get a sound out, Stiles' hand clamping down over his mouth.

"Hush," Stiles hissed in Derek's ear as they rolled through the water with the force of Stiles' impact. Derek had his fangs out and was giving serious consideration to sinking them into Stiles' hand until Stiles continued with, "there's a barracuda."

Derek relaxed and slipped an arm out of Stiles' loose grip to pull Stiles' hand away from his mouth. "That's Allison, she's my friend."

"You're friends with a barracuda? And somehow I'm too dangerous for you?"

"No, that's not-" Derek sighed and tried to get his thoughts in order. "She helped us out of a tough situation a while ago, and she's lived in the village ever since. I know she's peaceable, despite the shape of her tail."

"If you say so," Stiles said, but he sounded doubtful.

"Why did you come over here, anyways?" Derek wiggled a little in Stiles' hold. Now that the adrenaline had worn off he was becoming overly aware of how Stiles' tail had tangled around Derek's own, Stiles' scaleless skin cool and slick against Derek's fins.

"I thought you were about to be eaten by a barracuda! I was trying to save your life, you idiot!" Stiles squeezed his whole body where he was wrapped around Derek.

"Huh." Maybe Stiles had been being honest this whole time about his intentions.

Stiles snorted in response, but before he could add anything else they heard Allison calling out from below, "Derek, what's going on?"

"Everything's fine," Derek shouted back while he and Stiles spent an awkward moment untangling their tails.

Allison closed the distance between them in the meantime. "Do you know this person?" Allison asked Derek, sending a narrow-eyed glance at Stiles.

"Yes, he lives in the rocks just there." Derek pointed across the forest. "He thought you were going to try to eat me, so he came over in a misguided attempt to save my life."

"Hey, "misguided," what is that supposed to mean?" Stiles drew himself up.

"Oh, that was sweet of him." Allison's face unfurled into a smile. "I'm Allison, and I promise I don't eat people." She held out her hand towards Stiles.

"Um," Stiles squinted and looked between Allison, her hand, and Derek until Derek nodded at him. He took Allison's hand like he expected it to sprout claws at any moment. "I'm Stiles, and, uh, me neither."

"Great!" Allison laughed. "Why haven't I seen you around before?"

"I'm still kind of new to the area," Stiles shrugged. "And," Stiles batted Derek's shoulder with the back of his hand, "this guy has forbidden me from entering the village on pain of death or something."

"Derek," Allison frowned at him, "why would you do that?"

Derek rolled his eyes. "It might be because it's my job to keep strange predators out of the village."

"Do I not at least get some points in my favor for trying to save your life just now?" Stiles cut in before Allison could respond.

"Maybe," Derek admitted.

Allison beamed at him before turning to Stiles. "Of course you do. Derek here takes a while to warm up to people, but I'm sure now that you've proved your intentions there's no reason for him to keep you away!"

Stiles snickered. "I dunno, Derek's face is telling me a different story over there."

Derek scowled and then tried to arrange his face into something more neutral. He evidently failed, since Allison started laughing at him too. "Great," Derek grumbled. "Come on, Allison, let's get your weeds and go home."

"Of course," Allison agreed, still giggling, "I left them down below, let me just go fetch them."

"Hey, dude," Stiles said once Allison was out of hearing range, "you know you don't have to bring me to your village just because she said you should, right? I mean, I'm still very much not a threat, but I don't want you to do anything you're not comfortable with. They're your people, you know, you're allowed to be a little overprotective."

Derek stayed silent for a moment, watching Allison grab her bags and swim back up to their level a little ways away, waiting for Derek to finish talking. Stiles sighed and turned away, but Derek shot out a hand to grab his forearm and keep him from leaving. "You don't make me uncomfortable," Derek choked out.

"Really?" Stiles' eyebrows flew up.

"Really." Derek let go of Stiles' arm. "Not anymore, anyways."

"Awesome," Stiles face split into a grin. "Then, maybe I could finish out one of your patrols with you sometime? Make it all the way back to your village?"

"Yeah," Derek agreed, surprised by how okay he felt with that idea, "I think maybe you could."

"Perfect," Stiles' grin didn't look like it was going anywhere fast. "Then I guess I'll see you tomorrow morning, sweetfins."

"Yeah," Derek nodded, "I'll be here."

"I wouldn't miss it for the world. Now hurry along, your barracuda friend is waiting and I fully intend to enjoy the view while you swim away."

Derek rolled his eyes and faught down a blush as he swam toward Allison, feeling Stiles' gaze on him the entire way. If he happened to flare his fins more than necessary along the way, nobody needed to know about it.

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