Aquatic Companions

I'm getting together next week for my first ever Starfinder experience. I'm playing a Corpaxi who, basically, was abandoned on a high grav water world. I'm wanting him to have made a friend I can bring along on our adventures!

We start at level 1 BUT if it's a bit too high CR or something it can just be a untamed one that I'll focus on taming till appropriate.

Any thoughts? I'm very very new, and google is at a loss like me! HALP!

(edit was spelling error)

Interstellar Species has a few aquatic creature companions.

Or go through the whole list and look for ones with swim speeds.

Interstellar Species has a few aquatic creature companions.

Or go through the whole list and look for ones with swim speeds.

I love you.

(Edit: on that link to Interstellar Species thing, I'm not 100% sure what I'm looking for here.)

My PC is a Copaxi, bonus points if it's thematic!

His little friend would be something that can survive deep under water.
If I need some equipment or mod for the companion that's fine!

If needed I can beg for a homebrew; if it comes to that what would be a good reference?

Thanks gang!