Gamatatsu

is one of Gamabunta's children and Gamakichi's younger brother who has a fixation with snacks.

Personality
Gamatatsu has shown that he'd choose snacks over someone's life. When Naruto is injured while fighting with Kabuto Yakushi, he replies, "Hey Gamakichi, do we have to wait for the kid to croak till we get snacks, cuz' I'm getting hungry". Although in the filler arcs Gamatatsu showed that he does care about Naruto's life as he was ready to rescue him before Gamakichi talked him out of it. It should be noted that Gamatatsu appears to be the most subservient and loyal of the main frog summons as he was willing to serve Naruto before Gamakichi brought up the snack remark. While being naive and childishly stupid, he does sometimes make use of his natural curiosity to help Naruto solve puzzles (like the mystery of the Ghost Warrior in the Bird Country arc). Gamatatsu's obsession for snacks is so great that he waited a year since his first summon for the snack he was promised, even though he didn't get it. He is always hungry and asking his summoner for snacks, and often gets mixed up in unusual predicaments which he counts on his "big brother Gamakichi" to get him out of. In the english anime, his voice is jocularly high. He also openly refers to Gamabunta as "daddy", which the older toad either chooses to ignore or simply doesn't mind.

Search for Tsunade
Gamatatsu was accidentally summoned by Naruto Uzumaki in an attempt to compensate for Jiraiya's failed summoning. He was summoned again with Gamakichi as well by Naruto during the Noroimusha and Sea Country arcs for a scouting mission. As a summon, he seems like the antithesis of his older brother Gamakichi, being rather dull and humorously lethargic when compared to his fast-paced and smart-allec-y brother. Gamatatsu also seems to lack a sense of danger. When Orochimaru summoned Manda, Gamatatsu was too busy saying hello to his father to notice that the giant snake was staring at him. The young toad did not seem frightened in the least until Gamakichi told him to run. However, this fearlessness may also have been due to his titanic and overprotective father's presence or his lack of sense of endangerment.

Land of Birds
Gamatatsu makes a short appearance in the Land of Birds arc when Gamakichi and Naruto need him. Despite Naruto thinking he will be helpless, Gamatatsu using his curiosity finds a kite as a clue about how can the Cursed Warrior fly. Later, he goes down a dark tunnel with Naruto and Gamakichi and gets caught by the Daimyo and the guards. These event have led Naruto to believe that Gamatatsu can be helpful.

Three-Tails Arrival filler arc
Gamatatsu makes his next appearance during Naruto's synchro training. While having grown much larger since his last appearance, his personality has remained the same as he is still rather spacey and more concerned with food. While helping Naruto to master synchronization, his methods seem more about gaining food. He and Gamakichi seem to have a better relationship than when they were younger since Gamakichi doesn't call him an idiot. Gamatatsu has also learned a jutsu where he can make himself the same size as when he was in part I just like his brother. It maybe possible that Gamatatsu may grow up to be bigger than his father since Gamakichi was predicted to be as big as father. Naruto then learns that neither Gamatatsu or Gamakichi have mastered Water Elements like their father, but decides to continue working with them, since Naruto finds it more preferable than working with Gamariki.

Deciding to try and learn water element, Gamatatsu begins getting trained by Gamakichi with what appears to be the basics of water-chakra learned from their father. After several failed attempts at water-chakra which involved using already existing water stored in Gamatatsu's mouth, he finally manages a powerful water blast. Later when Naruto is assigned a mission as backup for Team 8, Naruto decides to perfect the combination jutsu before leaving. As Gamatatsu is still very new to water-chakra, Gamakichi devises a solution by having Naruto sit in Gamatatsu's mouth to better synchronize. Unfortunately, Gamatatsu continuously just spits Naruto out.

Later when Team 7 tries to break into a crystal labyrinth made by Guren, Naruto summons the two and prepares the technique with Gamatatsu. At first Gamatatsu forgets to mold the chakra and just spills the water out of his mouth, but during their second attempt, they successfully creates a torrent of water strong enough to demolish the entire crystal dome.

Quotes

 * "How you doing, Daddy?"
 * "Can I have a snack?"
 * "This is the first time anyone's ever summoned me! I'm finally getting a chance to shine!"
 * "Wait, they got snacks here? Gee wiz, this is the coolest!"
 * "Hey Gamakichi, do we have to wait for the kid to croak till we get snacks, cuz' I'm getting huuuuuuuunggggry."
 * (When he is under a kite)"Waah its dark! Its night, good night. (After Naruto picks up the kite) Good morning?"
 * "Big brother Gamakichi, how do you greet a giant mole?"
 * (Naruto says he is impressed by Gamatatsu being huge) " Its because of all the snacks we've been eating."
 * (Naruto mentions combination training) " Will it taste good?"