[Terr_]

> Hands wouldn't give a fish any advantage, because there is nothing to climb.

The ocean floor has plenty of stuff to dig into, pick up, and manipulate, along with un-anchored things like mats of seaweed.

> Land animals are more likely to develop hands.

I can easily imagine sea-creatures making the same kinds of assumptions in reverse: "Sir Blub-blub, while this hypothesis of 'land' animals is indeed intriguing, they would undoubtedly be primitive, far less likely to develop intelligent grabbers. After all, there will be nothing worth grabbing but hard 'dry' rocks! They wouldn't even be useful for propulsion, given the intangibility of this 'air'."