The shrimp welfare project

If you find this line of argument compelling, consider another alternative: engineering an organism which is much smaller and consumes far fewer resources than shrimp but which exists in a neurologically stable state of perpetual bliss. The survival and replication of this species of biological prayer-wheels would rapidly become a far stronger moral imperative (within the logic of the article) than any consideration for shrimp, or indeed humans.

I don't think this is the same at all. Creation of good is not necessarily as good as avoidance of harm is bad.

It depends on your goals, right?

If your goal is "maximize total happiness", then engineering blisshrimp is obviously the winning play. If your goal is "minimize total suffering", than the play is to engineer something that 1. experiences no suffering, 2. is delicious, and 3. outcompetes existing shrimp so we don't have to worry about their suffering anymore.

Ideally we'd engineer something that is in a state of perpetual bliss and wants to be eaten, not unlike the cows in Restaurant at the End of the Universe.