- "Do we really need that treasure? Isn't our friendship treasure enough?"
- ―Fishlegs while he and Hiccup are searching for Hamish II's treasure[src]
Hiccup and Fishlegs have known each other their whole lives. They have similar personalities; contemplative and quiet, smart and imaginative. And they have both experienced being unpopular among their peers. Fishlegs is more prone to acting a part in order to fit in, while Hiccup, though annoyed, accepts his social position. They've been friends at least since they were seven years old, when they spent Snoggletog together, and Hiccup has fond memories of how excited Fishlegs had been that year. Once older, they immensely enjoy learning new dragon knowledge and discussing it together, along with inventions and new discoveries. "Geeking out" has become their thing, to the point of at times greatly annoying their other friends. Of the other Riders, Astrid and each other are the only ones they've ever hugged.
After Hiccup starts displaying his talent at dragon training, the other teens start showing interest in him only because they're starting to think he's cool, while Fishlegs is more interested in learning what Hiccup knows. And when Hiccup is appointed the winner and gets to take the final exam, Fishlegs is so excited for his friend, he lifts him up into his shoulders and triumphantly parades around the arena with him.
Fishlegs becomes cautious when Hiccup introduces the other teens with his idea on how to defeat the Red Death and save their tribe. But once comfortable riding a dragon, he's quick to recite dragon facts again when Hiccup asks him. And he has no problem accepting Hiccup's sudden leadership position and assertiveness.
When Hiccup is thought to be dead after fighting the Red Death, Fishlegs appears to be holding his breath in shock. And at finding he's still alive, Fishlegs is emotional and can be seen breathing normally again.
At the end of the movie, only Astrid and Fishlegs join Hiccup in flying through Berk on their dragons; Fishlegs still getting the hang of steering his. The remaining three teens only appear in the background moments before the movie ends.
The two aren't shown to interact much, but Fishlegs is excited when Hiccup tells him and the others to grab their shields because they're going to help Gobber look for the Boneknapper. Hiccup is still one of the few showing interest in what Fishlegs has to say about this mysterious dragon, and looks concerned for his friend when Gobber suggests Fishlegs be the live bait in order to catch it.
Hiccup, Fishlegs, and Astrid, as the smartest of the group, are the only three teens studying and contributing to the Book of Dragons in the Great Hall. Hiccup writes down what Fishlegs suggests, though later in the franchise, Fishlegs becomes the official scribe of the book, and writes in it what Hiccup suggests.
Later, when Hiccup returns to Berk with all the dragons, including Meatlug, he's very pleased to see how happy Fishlegs and his other friends are at having their dragons back. And he enjoys watching them playing with the baby dragons their dragons had while they were away.
When the Riders are reminiscing about the start of Dragon Racing, Hiccup and Fishlegs don't really interact, but they do quite a bit in the flash back. Hiccup and Fishlegs are the only two Riders not enthused at their sheep catching task being made into a competition by the other Riders. After Stoick tells Hiccup that he'll be acting chief while he nabs some special wood for his Regatta boat, Fishlegs suddenly appears behind him and is greatly impressed with Hiccup being acting chief during the Regatta preparations. He then excitedly tells Hiccup about the project he's working on now that he's finally old enough to take part in the annual Regatta, though refuses to share details about it when Hiccup asks. Hiccup respects that, but returns later with Astrid to ask him to join their sheep catching team, to which Fishlegs refuses, stating he's much too busy with his Regatta preparations. After Astrid is injured and Hiccup is left without a team mate, Hiccup asks again, but this time Fishlegs finally reveals the boat he had been working on. Hiccup looks on amused at the ship as Fishlegs and Meatlug climb aboard. Within moments of setting off, however, Meatlug gets sea sick and spews lava into the bottom of the boat, causing a hole and the boat to sink. Fishlegs then finally agrees to join Hiccup in the Sheep Catching Competition.
In "Animal House", Fishlegs tells Hiccup and Astrid about body heat management, and how they could have kept each other warm longer while buried in the snow, to which the two recoil awkwardly. He then actively tries to help Hiccup figure out how to get the animals to not be so afraid of the dragons, coming up with the idea of taking the animals' perspective, and offering the chickens a Terrible Terror egg to sit on. When the teens are trying to chase down the spooked animals, Fishlegs stays and helps Hiccup despite being cold and wanting to go back to his house to grab his heavy coat.
In "The Terrible Twos", Hiccup is worried about Fishlegs after not seeing him for a while during a training mission, and goes looking for him. At finding him stuck in a tree, Hiccup attempts to help his friend down, only to pull his pants off instead. But despite Fishlegs' indignity, Hiccup remains respectful, and turns away while Fishlegs redresses himself. The two never bring the incident up again showing their mutual trust and respect for each other. Later at the arena with Torch, Hiccup allows Fishlegs the honor of doing the claw test, and then name this new species.
In "In Dragons We Trust", Hiccup tries to persuade Fishlegs to do a trust test with Meatlug, to no avail. He later gets annoyed with Fishlegs when his dragon knowledge starts making their dragons look guilty for the vandalizing of the Great Hall, even while Hiccup still insists their dragons are innocent.
In "Alvin and the Outcasts", Fishlegs refused to tell Alvin where to find the "dragon concurer" even when threatened with being thrown off the cliff. While hiding under a cart, he and Hiccup bump into each other, and Fishlegs warns him that Alvin is looking for him. After Hiccup gives himself up and has Alvin take him to Dragon Island, Fishlegs joins Stoick and the other teens in bringing Hiccup home safely.
In "Portrait of Hiccup as a Buff Young Man", Fishlegs and Meatlug help Hiccup in retrieving a piece of Hamish II's puzzle from a sea stack, even though the wind is seeing and it's making Fishlegs nervous. Later, Fishlegs and Astrid are the only two Riders desperately trying to dig Hiccup out after a cave in.
In "Dragon Flower", Fishlegs desperately asks for Hiccup's help when Meatlug starts acting sick. After the discovery of the Blue Oleander, Hiccup turns to Fishlegs and his knowledge on botany for more info on this flower that seems to be making all the dragons ill.
In "Heather Report, Part 1" and Part 2, Fishlegs is honest with Hiccup in how Stormfly is about to match Toothless' speed. It's also revealed that Fishlegs writes what Hiccup tells him to in the Book of Dragons. When trying to rescue Astrid from Outcast Island, Fushlegs follows Hiccup's lead on the mission.
During a quick scene in "Thawfest", Fishlegs covers his eyes in fear of Hiccup getting hurt, or worse, during the Cliff Climb part of the games. He and Astrid also discuss how neither of them have ever seen Hiccup gloat before and how it's so unlike him.
In "When Lightning Strikes", Hiccup questions Fishlegs in the making of the Thor statue's pants, and although he didn't quite understand Fishlegs' motives, he trusts his friend and allows him to finish.
In "What Flies Beneath", Hiccup and Fishlegs spend some time alone in the Whispering Death tunnels. Fishlegs was frightened at first but at Hiccup's encouragement, starts to feel better. Fishlegs first notices the Night Fury bite mark on the Whispering Death's side and discovers that it and Toothless have a history. He and Hiccup mutually try to defend each other from the wild dragon while in the tunnels, and Hiccup helps Fishlegs get out of the tunnel first, seemingly martyring himself.In "Twinsanity", Fishlegs tells Hiccup about his new hand signals, and the two decide to work on more together. Later Hiccup is the only one supportive of Fishlegs' new battle technique, having Meatlug "hug" the enemy.
In "Breakneck Bog", Hiccup teams up with Fishlegs and Astrid again to look for Johann's ship and a treasure left from Hiccup's mother. Fishlegs offers Hiccup his own mother in exchange for going after the "fog monster", reminding him that he lives huts mother's crabcakes. When Hiccup finally gets the chest with his mother's treasure in it, a Smothering Smokebreath grabs his leg, but is beaten off when Fishlegs flies by on Meatlug and whacks it away.
When everyone else is rushing Fishlegs in "Gem of a Different Color", Hiccup and Astrid try to protect him. And when he blames himself for all the trouble caused by the Changewing egg, Hiccup reassures him that it could have happened to anyone and he's not to blame. And then Hiccup gets irritated at Astrid when she says Fishlegs being to blame is right. At the end, Fishlegs explains exactly what the new dragons look like to Hiccup, while Hiccup draws them in the Book of Dragons.
In "We Are Family, Part 1" and Part 2, Hiccup is impressed at Fishlegs going above and beyond in not only calling his own dragon but also a whole herd of Gronckles. He gets annoyed at him later at his on point Thunderdrum call, however. After Hiccup is captured by the Outcasts, Fishlegs joins Stoick and the other Riders in rescuing him, and is overjoyed when they are reunited.
- "Fishlegs and Meatlug... Against a giant Typhoomerang. Does that seem fair to you?" -Fishlegs
"Nope, the Typhoomerang doesn't stand a chance!" -Hiccup"
In "Live and Let Fly", Fishlegs is tested under pressure by Hiccup and the other teens into releasing info on the Riders, and when he breaks down, Hiccup is the only one he has nothing negative to say about. And later when he holds firm when questioned by Stoick and Gobber, Hiccup praises him.
In "The Iron Gronckle", Fishlegs feels bad for holding the rest of the team up with his slow dragon. Hiccup attempts to encourage him, but reluctantly gives in when Fishlegs insists on staying behind during a search for an Outcast ship. After Fishlegs discovers Meatlug's ability to make Gronckle Iron, Hiccup tries to recruit Fishlegs back into helping him and the others, only for Fishlegs to again insist he's needed more by the villagers. When Meatlug becomes magnetic, Hiccup helps Fishlegs chase her down and initially ignores Fishlegs' warnings about his metal leg. Soon Meatlug is flying off with Hiccup attached to her belly by his leg, and Fishlegs flies after them on Toothless. Hiccup attempts to apologize to Fishlegs for passively suggesting he sit out of the recent missions, while Fishlegs awkwardly tries to get Meatlug to spew so they don't have to talk about their "feelings". Hiccup suddenly sees an Outcast ship, and Fishlegs finally manages to get Meatlug to spew the rocks that made her magnetic, thus dropping Hiccup and the other metal attached to her. Fishlegs had Toothless catch Hiccup, while the other metal crashes onto the Outcast ship, and sinks it, leaving Hiccup and Fishlegs exuberant at their teamwork. Fishlegs finally discovers he's still important to the team and rejoins the Riders.
In "The Night and the Fury", Hiccup encourages Fishlegs when he's frightened over spending the night alone on Dragon Island. Later, when he runs into Hiccup and Dagur, he catches onto Hiccup's hinting immediately, unlike Snotlout who almost gave their original intentions away.
In "Tunnel Vision", Fishlegs helps Hiccup scale down the inside of a dried up well. When Stoick arrives, worried for his son, Fishlegs expresses full confidence in his friend and tries to help Stoick relax. When the Screaming Death appears, Hiccup immediately turns to Fishlegs for any info he might know on it.
In "Fright of Passage", Fishlegs researches the Flightmare to discovers why it rampages through the village every 10 years, and flies to find Hiccup and Astrid to share his findings. When he gets frozen by the dragon, Hiccup has Toothless put him back on Meatlug's back for safety. The three then work together to encourage the dragon to head in another direction.
In "Worst in Show", Hiccup is impressed with Fishleg's rescue technique when no one else sees its use. He's the first to run after Fishlegs too when Meatlug is dragon-napped by Alvin to help him retrieve his dragon. After chasing the Outcasts to their ship, Fishlegs rides with Hiccup on Toothless as they use their new Terrible Terrors to help release Meatlug.
In "Appetite for Destruction", Hiccup admits that he and Fishlegs had come up with "Air Mail" together, and trusts his friend to get the message he's sending home. Sure enough, Fishlegs receives it and brings Snotlout to Dragon Island where Hiccup asked them to meet him and Astrid. Hiccup later entrusts Fishlegs to monitor Dragon Island alone while he and Astrid try to find out what's been demolishing while islands, and Snotlout and the twins retreat back to Berk.
- "Ugh, I hate it when they get like this. If someone doesn't fill me in right now, I'm getting my axe!"
- ―Astrid over Hiccup and Fishlegs' geeking out[src]
In "A View to a Skrill, Part 1" and Part 2, Hiccup and Fishlegs geek out together over the finding of a Skrill, much to the annoyance of Astrid. They run off to study it together in the Book of Dragons. And they're so excited about sharing their findings with Stoick. They then help each other in trying to prevent Dagur from catching it.
They don't interact much again in "The Flight Stuff", but Fishlegs is fully supportive of Hiccup in insisting that Snotlout isn't dying.
Apparently in "Free Scauldy", Hiccup got first and second choice on who was going to join him on a mission to Changewing Island, and Fishlegs was the first he chose. When Fishlegs starts freaking out over the Changewings and the stranded Scauldron, Hiccup calms him. But not enough to where, when Hiccup holds his hand out to demonstrate to Ruffnut how to train the wild dragon, Fishlegs approaches his hand and pressed his nose into it before Toothless could get to it.
In "Frozen", Fishlegs is the only one left in the village when Hiccup returns with Johann. When Hiccup enters Fishlegs' house after seeing movement inside, Fishlegs falls from the loft and accidentally lands on Hiccup, temporarily knocking him out. When he awakes, Fishlegs apologises for falling on him and gives Hiccup a big hug. He then tells Hiccup about the Speed Stingers and leads him to where Meatlug had been frozen where she stood. The two and Johann then travel to the cove where the rest of the village had attempted to take refuge. Hiccup later asks Fishlegs for everything he knew about these new dragons, and worked together in driving them off.
In "A Tale of Two Dragons" Fishlegs helps Hiccup find out why Stormfly and Hookfang are fighting, while Hiccup works with the two dragons' riders. At the discovery of Dragon Root, Hiccup helps protect Fishlegs and Meatlug from the other dragons while they try to dig it up so it can be discarded.The two spend a lot of time alone on Eel Island in "The Eel Effect" after Hiccup doesn't return and Astrid sends Fishlegs out to look for him. The two are overjoyed to finally find each other. Hiccup helps himself to Meatlug's saddle bag and Fishlegs' net as if knowing they mutually share them. He later attaches his shield to Meatlug's saddle and leaves it with Fishlegs while Hiccup tries to wrangle Toothless, who is going wild after eating an eel. When a wild Typhoomerang appears, Hiccup encourages Fishlegs to fight it off alone, saying that it doesn't have a chance against him and Meatlug. When the wild dragon is finally fought off, Fishlegs quickly returns to help Hiccup, even using Meatlug to sit on Toothless so Hiccup can force feed him the medicine he needs to recover. While Hiccup tries to soothe Toothless, Fishlegs makes the medicated stew, and finally Toothless regurgitates the eel and starts to feel better. They finally get back to Berk, and while writing about the effects of eels on dragons at Fishlegs' house, Hiccup sincerely thanks his friend for all his help. Overcome with sentimentality, Fishlegs runs and gives Hiccup a huge hug, though they're both almost smothered by Meatlug who also joins in.
The two don't interact much in "Smoke Gets in Your Eyes", but they both help Gobber carry his new scrap metal off of Johann's ship. Fishlegs is quick to help Hiccup in his plan to use the Smokebreaths to sink Dagur's armada and return the village's metal.
In "Bing! Bam! Boom!", Hiccup has Fishlegs hover far out over the sea to demonstrate the Thunder Ear for Stoick. Fishlegs later supports Hiccup's idea of training the baby Thunderdrums, and is the first to remember the calming effects of Dragon Nip so Hiccup and the Riders can finally get some peace. He then tries to help Hiccup keep the babies on Dragon Island and fight off the wild dragons that keep giving the little ones a hard time.
In "Cast Out, Part 1" and Part 2, Fishlegs acts protective of Hiccup and Toothless, and is quick to assist again when Dagur plants Dragon Root in the Academy so the dragons will fight each other and kill their riders. Hiccup is torn and frightened when his friends are all locked inside with the angry dragons. When Stoick finally manages to open the Academy doors so Fishlegs and Meatlug can escape with the Dragon Root, Hiccup has Toothless distract the other dragons so Fishlegs can escape safely. After Hiccup and Alvin make their way to Outcast Island to rescue Stoick, Hiccup sends instructions home via Air Mail, and in response Fishlegs agrees to lure the scariest dragon he knows; the Screaming Death, to Outcast Island with the Dragon Root in order to help his friend. After the wild dragon had been delivered, Fishlegs then helps fight off the Berserkers so Hiccup and Stoick can get away. Once peace is restored in Berk, Fishlegs is seen adding to the Book of Dragons while Hiccup recounts what great friends he has.Fishlegs comes up with the name "Hicclegs" in response to Snotlout and the twins' name "Snotnuts". The two work well together and give the other team enough to recon with that the twins turn to cheating as a sure way of winning. While Hiccup and Fishlegs are trying to see if the extra-pointer Black Sheep was in the well, the twins fly by with what appears to be the black sheep, making it appear that "Snotnuts" won this round. However, back at the arena and after the other team is pronounced the winner, Fishlegs appears with another black sheep which he had pulled out of the well, and the one that the twins had turns out to have been painted black. Astrid, as the referee, announces a reversal and declared team "Hicclegs" to be the winner.
- "I've known Hiccup all my life and he is my best friend, Dagur. Whenever I've needed him he's been there for me. And now he needs me!"