Araquanid’s 50 Special Attack isn’t going to do you many favors. But then again this is a playthrough, so anything works. I’d say with rain and Watter Bubble plus a nature supporting Special Attack, Araquanid could hit pretty hard with Surf, but is that effort really worth it? It would be meh.
I would in fact suggest a completely different Pokémon in the form of Pelipper. It’s pretty common and with the ability Drizzle, it automatically gets rain plus always hit powerful Hurricane in rain. Its Special Attack is much more impressive at 95 and to top it all off it can learn Ice Beam via TM. Hope I helped!