Pikachu is Ash's best friend. Pikachu has always been there for Ash and also takes a leader position for the team. He is curious and friendly, but shares Ash's fondness for battling. One of his most noticeable features is his determination and unwillingness to give up when a situation gets tough. He is shown to be responsible with younger Pokémon, particularly Misty's Togepi, who he is often forced to shepherd out of danger by putting himself in it. Although stubborn at times, he obeys Ash's commands in battle and rarely leaves his side. He is also a constant target for Team Rocket. They tried to capture him, but, on the few occasions that they do, their plans are always thwarted by Ash and his friends. Even after getting out of their traps or that he didn't get captured, Pikachu also thwarts his enemies by attacking or getting rid of them using his Electric-type moves.
Pikachu was Ash's Starter Pokémon, given to him by Professor Oak. Ash showed up late to pick his first Pokémon so he got stuck with Pikachu. Though he didn't like Ash at first, Ash demonstrated willingness to sacrifice himself for Pikachu, and they quickly became friends. Pikachu, who is rather independent in general, believes that he is strong enough without evolving and refuses to evolve into a Raichu even when he was easily beaten by Lt. Surge's Raichu. Later in Ash's adventure in the Sinnoh region, Pikachu was given another chance to evolve after being seriously injured by another Raichu but once again he refused.
Early in the series, Pikachu was given an operation to increase the strength of the electric sacs in his cheeks in order to beat the first Gym Leader, Brock. Despite this, Pikachu can also get a cold and go out of control when he cannot release his electricity. Most notably, exposure to a magnetic field will cause Pikachu to get a cold. This has been done to him three times in the series, two times by Team Rocket and one time by Zekrom: the first time, Pikachu was cured when the extra electricity was used in attacks against a group of Grimer and a Muk, and in the second time was inadvertently cured by one of Team Rocket's battery robots, which subsequently overloaded and exploded. The last time is when Professor Juniper heals him after Ash's battle with Trip in Unova.
Many of the Pokémon animated shorts with all-Pokémon dialogue have featured Pikachu as the main character, and as the main voice of reason. As such, Pikachu is often a leader, helping to break up conflicts among other Pokémon.
A running gag is how he burns all of main female character's bike with Thunderbolt, which, in turn results in that girl following Ash, except for Iris following Ash after she and Ash bumped into each other. Pikachu also has a fondness for ketchup, which is seen multiple times in the anime.
|Thunder Shock||Pokémon - I Choose You!|
|Thunderbolt +||Showdown in Pewter City|
|Agility||Electric Shock Showdown|
|Quick Attack +||Electric Shock Showdown|
|Thunder||Abra and the Psychic Showdown|
|Double-Edge||Friend and Foe Alike|
|Tackle -||The Double Trouble Header|
|Leer -||Hour of the Houndour|
|Iron Tail +||All Things Bright and Beautifly!|
|Volt Tackle||May's Egg-Cellent Adventure|
|Electro Ball +||Dancing With the Ducklett Trio!|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.
- Electric Slam
- Rocket Punch
- Thunder Armor
- Swift-Quick Attack
- Thunder Tackle
- Volt Tail
- Counter Shield
- Thunder Whirlpool
- Hydro Volt Tackle
- Electro Bolt
- Massive Electro Ball
- Electro Iron Tail
- Draco Meteor Climb
- Aura Sphere Climb
- Ikue Ōtani (Japanese; in both the Japanese and English-language versions of the Pokémon anime)
- Rachael Lillis (English; in some episodes of the English version of the Pokémon anime)
- Kayzie Rogers (English; Pokémon Learning League)
- Claudia Motta (Spanish)
- Sabine Bohlmann (German)
- Pikachu is Ash's only -type Pokémon and was the only Electric-type owned by a main character in the anime until the capture of Dawn's Pachirisu.
- When Ash received Pikachu from Professor Oak, his Poké Ball had a lightning bolt on the top part.
- Because Pikachu doesn't like being inside his Poké Ball, it has only been seen a few times since the first episode. The first was against Brock when Pikachu was being attacked brutally by Onix and the second was in the episode Snow Way Out when Ash becomes worried about the safety of his Pokémon in the cave's freezing conditions. Both times Ash's attempted return of Pikachu was blocked, by Onix the first time and by Pikachu the second.
- Pikachu had a chubby appearance in the beginning of the series, but lost the weight for a more slender appearance Generation II onward.
- Ash attempted to evolve Pikachu with the Thunder Stone after he lost to Lt. Surge's Raichu, but Pikachu chose not to evolve because he wanted to prove that he could defeat stronger Pokémon without evolving. This makes him the first of Ash's Pokémon to choose not to evolve.
- Pikachu occasionally has acted as a responsible leader of the main cast's Pokémon, mainly Ash's Pokémon.
- In the season one episode "Showdown at Dark City," Pikachu displayed a strong fondness for ketchup. In fact, when the ketchup bottle he was carrying was smashed, Pikachu was seen crying over the smashed ketchup bottle. This could be an indication on how close Pikachu's relationship with Ash is, since his last name is phonetically similar to ketchup.
- In the Season One episode "Ash Catches a Pokémon," when Team Rocket was trying to steal Pikachu, Meowth accidentally says that Ash's Pikachu's power exceeds the power level he would possess as a Raichu.
- In Climbing the Tower of Success, a Thunder Stone was tossed to Ash, thus it almost landed on Pikachu which would cause him to evolve. However, Ash was scared about Pikachu evolving, so he prevented this, which contradicts to the time he offered Pikachu a Thunder Stone to evolve. The most likely reason is that Ash now knows Pikachu doesn't want to evolve (and likes keeping him the way he is and respects his wishes), which is supported in the Diamond and Pearl generation episode Pika and Goliath.
- Both Ash's Pikachu and Snorlax are evolved baby Pokémon, but in that generation they are the first forms.
- Pikachu had a special event for the Generation IV of Pokémon Games knowing the moves Pikachu had in Sinnoh League Victors.
- Ash's Pikachu is a male, because male Pikachus' tails have straight ends, while females have a tail end similar to the top of a heart.
- Pikachu seems to have a great dislike, or even hatred, against Team Rocket's Meowth. As after Meowth and his team got away from the failed rail road mission in Unova, Pikachu still exerted a lot of anger and Ash had to hold him down. While Meowth was in Ash's group, Pikachu was the one to always be suspicious of Meowth's loyalty. This could stem from the fact that every time Pikachu started to trust Meowth, Meowth then betrayed that same trust.
- Ash's Pikachu is the most recognizable Pokémon, therefore being the main face of Pokémon.
- Somehow, for every region Ash has traveled through with Pikachu, he has always been for the most part surpassed in power by another Pokémon that Ash catches and trains until they fully evolve or learn new moves.
- Beginning from Hoenn onward, every time Ash and Pikachu enter a new region, Pikachu has been exposed to high levels of electricity or magnetism, before or after arrival, and loses control of his own electricity, becomes confused, and runs away, forcing Ash to chase after him.
- This could explain why Pikachu's strength is "reset" each time they start a new region, with the exception of Kalos.
- Pikachu has had many moves over the seasons, but the amount it now actively uses has been lowered to only four.
- Despite Pikachu's absence from the Unova Dex and not being native to the Unova region, a Trainer's Pikachu can be seen in Castelia City, and another Pikachu is depicted on a billboard. Also, there are several Pikachu-shaped hedges in Striaton City.
- Pikachu's hatred of being in a Poké Ball made him the last and hardest to be captured by Mewtwo in the Pokemon movie Pokémon the First Movie.
- Pikachu is the only Pokémon in the anime to defeat two Legendary Pokémon without being a Legendary Pokémon himself. His first victory against a Legendary Pokémon was when he defeated Brandon's Regice and the second was when he knocked out Tobias' Latios, although the battle against Latios ended as a draw rather than a victory.
- Pikachu is the first of Ash's Pokémon to defeat a Mega evolve Pokémon.
- Pikachu was also the first of Ash's Pokémon to habitually disobey him. Primeape and Charizard would also follow suit and are better remembered for their disobedience than Pikachu.
- Pikachu learned no moves during Diamond & Pearl series.
- Pikachu mostly blasts off Team Rocket using his Thunderbolt attack.