The Pokémon anime is one of the most popular forms of media in the franchise. It follows the adventures of Ash Ketchum and his friends as he tries to become a Pokémon master. His first Pokémon was Pikachu and he has caught a lot of others since.
Though he hasn't caught nearly as many as other trainers, Ash has given all of his Pokémon a lot of care since the first season. He has always tried to do what is best for them, even if he had to do something he didn't want to. Throughout the first 52 episodes, a lot of his Pokémon became very powerful, but which one was the strongest?
11 Krabby
When Ash caught Krabby, he was surprised to find out that he could only keep six of his Pokémon with him at once. He already had Pikachu, Butterfree, Pidgeotto, Bulbasaur, Charmander, and Squirtle with him, which caused Krabby to go to Professor Oak.
Fans did not get to see much of Krabby in the first season but since Ash was able to catch it without bringing any of his other Pokémon out to battle, the anime knew that Krabby was one of his weakest Pokémon back then.
10 Raticate
Ash had Raticate for a very short amount of time. He met a man on the St. Anne and the two of them battled. Ash used his Butterfree while the man used his Raticate. Impressed by each other's Pokémon, Ash traded his Butterfree for Raticate.
However, when Ash regretted the trade, the man agreed to give Butterfree back to him. In their battle, Butterfree was clearly the winner. Whether Raticate was using its full power against Butterfree and still lost or if fans did not get to see what Raticate can really do is unknown. Either way, the rat seemed to be pretty weak.
9 Muk
Muk only appeared in one episode in the first season. Ash caught Muk after Pikachu and a wild Magnemite teamed up and used their electric abilities to weaken it. It didn't take much and Muk quickly lost the fight.
The strongest thing about Muk was how badly it smelt, causing Ash and the others to hold their breath, even when the Pokémon was in its Poké Ball. Professor Oak was not too happy to receive the smelly sludge Pokémon.
8 Butterfree
Caterpie was the first Pokémon that Ash caught. He watched it evolve into a Metapod, followed by a Butterfree. Unlike most of Ash's Pokémon, he would not be with Butterfree for too long as he had to say goodbye when the Pokémon fell in love.
It was very hard for Ash to let him go but he was thankful for all that they had been through and how Butterfree had helped him on his journey. Though Butterfree was not Ash's strongest Pokémon, he did teach him how to be a stronger trainer as he did what was best for his Pokémon.
7 Haunter
When Ash failed to defeat Sabrina, a Gym Leader who uses Psychic-type Pokémon, Ash found out that he would have a better chance of winning if he caught a Ghost-type Pokémon. After encountering a Gastly, Haunter, and Gengar, Ash became friends with them and they wanted him to stay with them since they were lonely.
Sad to see Ash leave, Haunter decided to join him on his quest and helped him win his battle with Sabrina by making her laugh. Prior to this, Sabrina was not capable of showing her true emotions. In order to keep her happy, Haunter decided to stay with her.
6 Squirtle
The Water-type starter Pokémon was abandoned and became the leader of a group known as the Squirtle Squad. However, after meeting Ash, Squirtle decided to join him and helped him a lot in his adventure.
Squirtle was very useful whenever Ash needed a Pokémon that could swim. Due to how tough Squirtle can be, it was also very helpful in battles. As Squirtle stayed in the group longer than Raticate, Haunter, or Butterfree, it became good friends with Pikachu and the other starter Pokémon.
5 Pidgeotto
After Caterpie, Pidgeotto was the next Pokémon that Ash caught. Pidgeotto was used in a lot of Ash's earlier battles, and it would continue to be part of the trainer's team until the opening episode of the Orange Islands arc.
Though it did not defeat many opponents on its own, Pidgeotto was often used in order to weaken an opponent's Pokémon. Ash would call Pidgeotto back and summon one of the others in order to finish the job.
4 Bulbasaur
When the two of them first met, Bulbasaur did not like Ash and his friends. Bulbasaur thought they were trying to harm the injured Pokémon that it swore to protect. However, it decided to join Ash and became one of his most loyal Pokémon.
Ash used Bulbasaur in some of his most important battles throughout the season, including multiple gym battles. Like Pikachu, Bulbasaur also had the opportunity to evolve but refused, making it a very strong Pokémon despite that fact.
3 Primeape
Though Ash only had Primeape for a short period of time, the Fighting-type ape was one of his strongest Pokémon. When they first met, Primeape was a Mankey. Mankey ate some of Ash's food and stole his hat, causing Ash to get upset. After being attacked by Team Rocket, Mankey evolved into Primeape and became very aggressive.
Ash used his Charmander to weaken Primeape and caught it. Not too long after, Ash met a Fighting-type Pokémon trainer named Anthony. Ash gave Primeape to Anthony, hoping that Primeape could become one of the strongest of its type in Kanto and a P1 champion.
2 Charizard
Charizard first met Ash when it was a Charmander. It was abandoned by its previous trainer and nearly died in a storm until Ash saved it. Charmander became one of Ash's most loyal Pokémon and helped him win many battles until it evolved into a Charmeleon.
Unlike when it was a Charmander, Charmeleon disobeyed Ash. It became even more rebellious and lazy when it quickly evolved again, this time into a Charizard. If it had continued to be obedient and helpful to Ash, Charizard could have been his strongest Pokémon.
1 Pikachu
Pikachu, despite not liking Ash when they first met, has become his most powerful Pokémon. The two have been through a lot together since the series began and have remained close to this day.
Pikachu saved Ash from a flock of Spearow in the first episode and has been helping his trainer ever since. There are even times when the electric mouse wants to battle more than Ash wants him to. If it were not for Pikachu's strength, Ash would not have become a Pokémon Master.