1st Gen Who is the best water pokemon?

There are so many good options from first gen Slowbro, Starmie, Gyarados, Blastoise, Vaporeon, Lapras, Cloyster, the list goes on.

Which pokemon do you think is the rightful king of the sea?

Seaking because it's in his name

Lapras

Mechanically, I feel like Greninja is...

But Feraligatr, otherwise...Cause he is the greatest...

For Gen 1, it would have to be Lapras imo. It has a very diverse movepool and has access to Thunderbolt as well as powerful STAB attacks.

Ooh that's a hard choice, considering there's so many good water type Pokemon in Gen 1! I'd say the title easily goes to Starmie. Starmie has a great special stat and high speed. It has plenty of solid moveset options such as Thunderbolt, Psychic, and Ice Beam. It's also a Psychic type, one of the best types in Gen 1.