same as eny other Pokemon game with a fishing rod!
Gligar is a flying and ground type of Pokemon. The only way to get this Pokemon in LeafGreen version is to trade for it.
Manaphy is a legendary water type of Pokemon. It is not possible to get this Pokemon in the game Pokemon LeafGreen.
No, you cannot catch a Chinchou in Pokémon FireRed. Chinchou is a Water/Electric-type Pokémon that is exclusive to Pokémon LeafGreen. If you want to obtain a Chinchou, you'll need to trade from LeafGreen or transfer it from a different game where it is available.
Yes there is even some johto Pokemon in there which are swinub, delibird(firered only), sneasel(leafgreen only) and many more water type Pokemon.
All Pokemon with a water-type can learn it. There are some other Pokemon that can learn it, but mostly water-Pokemon.
Yes. Kabuto (a Rock/Water type pokemon) can evolve into Kabutops (also a Rock/Water type pokemon) at Level 40.
If it's held by a Pokemon it will boost Water type moves.
An electric type, water type, psychic type, ice type, grass type, fire type.
The best water type would be Kyogre but you can't get it in leafgreen you need to get one from sapphire or emerald other than that the best water Pokemon is blastoise.
catch a vulpix in the route from lavender town to celadon. or simply pick charmander as your starter
In HeartGold you can catch Kyogre.
Yes, Krabby is able to learn Surf. After all, it is a Water-type Pokemon.