I couldn't care less for such an idea.
I think aquariums is boring as it is. How would taking care of virtual pets be any different? Yeah. Feeding, grooming them, play with them, whatever. It just doesn't feel all that interesting. Virtual pets are nice for those who don't own pets. But I do, and I feel that messing with a virtual pet when I have my own real ones would just be silly, even if Gaia bribed me with shinies. *Raises defensive shield*