It depends. When one of my fish die, I do get another one.. because it opens up housing for another betta (didn't mean to make that sound that heartless )

If one of my birds died, I wouldn't run out and get another.. unless it was Ozzie as he's my only really sweet one that loves people. But I wouldn't get one right away.. maybe months down the road or even a year.

If one of my dogs died, I know nothing would replace Kai or Kae. I wouldn't go seeking a dog right away but if one that was less than fortunate came to me, I probably would take it in.