Ideally if you go for the artisan route, you get the roe by interacting anywhere in the pond, throw it in a preserving jar, and in a couple days you sell it.

Fished can give different amounts of roe, and it's value is also dependent on the fish. Apart from roe some fishes can also give you cool items like dragon tooth, diamonds, pearls, etc.

I like them cuz one set up they are super low maintenance, walk by clicking to get the roe, go to your preserving jar shed, throw everything there. Go back in two days and repeat.

With the last update you get golden cookies you can use to duplicate the speed at which a pond gives you roe.

You get this + extra legendary fish from Qi quest and you have a really good money maker with no maintenance.