No alphas, and no bettas either please

I know that dog bloggers are a sophisticated bunch, used to dealing with complicated psycho-social matters like blended families, rescuer martyr complexes, animal welfare concerns, and everything in-between. So maybe you can help me out with this one.
 
Let's just say hypothetically that a non-custodial Dad wants to give his 13-year-old son everything, maybe because he loves his son very much and maybe also because he feels a bit guilty that he is not the custodial parent, as I believe many divorced fathers do. And let's just say that said Dad is with his son during one visitation weekend and goes to a pet store, and said child begs for a pet Betta fish. A pet fish who will live at the noncustodial house, that the child will see and care for every other weekend, in between which times, the noncustodial father, and more than likely the girlfriend, will care for the fish, feed it, clean its pathetically small tank, and watch it flitter its fins aimlessly in place in a sad parody of what it might do in its native rice paddies in Thailand. 


Now let's say that said girlfriend has always felt a constriction of the chest and a sinking of the heart every time she sees a Betta fish in a store, with no life except to sip air from the top of its tiny bowl, day in and day out, until it dies a premature death of boredom, having lived a life that bears no semblance to what it was born to do. 

And lets just suppose that said girlfriend already feels a burden of responsibility that is sometimes almost unbearable, toward the budgies that also live with her, who were also the result of an impulsive decision on the part of said boyfriend, and toward the dogs who live with her, and toward the millions of dogs and cats whom she is unable to foster, who die in shelters because she is unable to foster them. And let's just suppose that said girlfriend feels overwhelmed at the thought of another life that feels like her responsibility--because let's face it, the day to day work of caring for the budgies and the dogs has fallen almost exclusively to her--and horrified at the thought of living with a creature whose existence, in its tiny bowl, is a daily reminder of how miserably we humans have failed other species. 


Should said girlfriend feel like an ogre for insisting that the fish go to the custodial parent's home with the child, or back to the store, or to the Humane Society? For believing that this child and this boyfriend need a lesson in responsibility? 


Just hypothetically, of course!