Would you feel so strongly if that were a case of stealing an empty notebook? Why is it that people are feeling so fired up about the ownership of a living creature and protect their rights to own them more than the rights of the living creature? The slave master genes?
If you see me keeping my dog at the equivalent conditions of a betta in a dirty, manky cup of water, then my answer is yes. For your disappointment, you wont' see me doing that.
For your information, they are literally on equal ground. We all walk the same Earth..It only takes the right point of view to see it. Then again you can ignore my view because you won't like it. I think we humans can be defined as parasites, benefiting from the suffering of other creatures, and even our own kind.
Riddle: What is something that has no rights, that you can abuse, or stab or cut or eat, or choke or poke the eyes out as you please?