Meganium does not appear in fire red. You need to complete the a task on emerald for you to get either cyndiquil, totodile or chikorita. Chikorita evolves into bayleef at level 16, and then into meganium at level 36.
Meganium is #154 in the national pokedex, and it is a Grass type Pokemon.
get the complete pokedex from prof. oak. go to the sevvi islands and do missions there. get mewto in cerulean cave. complete your pokedex.
Squirtle is only obtainable if you chose it at the beginning of the game you must get one from another firered or leafgreen then give it to your firered and then you can finish your pokedex.
Meganium or nine tales
If i am right you have complete your kanto(???) pokedex. I don't know if it is kanto or national.
You have to complete all 202 Pokemon on the Hoenn Pokedex. When this is done, Professor Birch will call you on your Pokenav. Go to his lab and you can select Chicorita, then raise it.
look in your pokedex
If you complete the pokedex you can get a diploma from game freak in the celadon mansion in celadon city and you can now say to everyone you did it!
you could look for it but is too hard, so you have to see all the Pokemon in your pokedex so you could upgrade to a national pokedex then go to the professor he should let you pick one Pokemon from the johto region it should be the first of meganium "chikorita" and two other Pokemon.
You have to catch 151 pokemon to complete the pokedex.
catch 80 Pokemon
u could complete the pokedex