* Type Matchups: Water is weak to fire, making it illogical for a water Pokemon to learn fire attacks. It would go against the core mechanics of the game.
* Move Tutors and Breeding: While some Pokemon can learn moves outside their natural movepool through move tutors or breeding, these options are generally limited to moves of the same type or moves that fit their Pokemon's evolutionary line.
* Special Cases: There are a few exceptions, like certain events or special abilities, where a water Pokemon might get a fire attack temporarily. However, these are not standard gameplay mechanics.
Therefore, you won't find a water Pokemon learning a fire attack through normal gameplay in the Pokemon games.