I don't have any real expertise with tunicates, and I doubt that many here will claim any either. They are a wide range of shapes, environmental preferences, habitats and more. I think most tunicates are a lot like most sponges, difficult if not impossible to keep in a typical marine aquarium. Probably the best thing you can do is identify the type of tunicate you have and then try to research it.
Do you have a picture of yours?