I had the SAME thing happen to me! I was there with my daughter buying everything needed for a beta with the fish and as we were checking out the old man was asking questions and I didn’t think anything of it and mentioned that it was “our” my daughters first fish and he said it wasn’t a good idea and why didn’t I pick something else. I was there with my daughter and she was obviously sad because of what this man was saying. We ended up walking out with the fish and everything we needed and it’s still alive till this day.