You can get a Squirtle after you obtain all 16 badges and defeat Red.
You have to beat red and then go to professor oak's lab
these are the Pokemon i know that are in heart gold version: bulbasuar,charmander,squrtle,caterpie,kaukuana and stelliks.
charmander squrtle (sorry if i spelled squrtle wrong) and bulbusaur
there is no fossils of squrtle in any game
well one thing you can do is go to profesor oak and get charmander squrtle or bulbasuar. and you can go to mr Pokemon and get an orb and go to embedded tower to get groudon or kyogre
squrtle
Pick it as your starter Pokemon at the beginning of your game.
at level 16
level 10
To get bulbarsaur you first get the the national pokedex then go to pallet town and talk to professor oak then he gives you a choice out of bulbasaur squrtle and charmandarAfter you beet the Pokemon league go see professer oak and beet red then get a starter from him
You cannot find Squirtle in Pokémon Crystal.
Beat Lt. Surge first.