I can understand that and encourage telling people to do research before purchase but I'm totally against all animals being there. I've had so many bad experiences (except in the case of my rat, but he was very special) with all sorts of animals.
I have 7 male and 4 female Betta fish, too and since learning more about them I am disgusted at the types of things fish-mills do to their fish. Some places even inject them with dye to make their colours more prominent. They're often sold when they're much, much older so that their colours have fully developed. So the fish you get could be 1-2+ years old and they have a short life expectancy, so they spend the first part of their lives in a very confined space. Fair enough they can live in puddles, but technically humans could spend their entire lives in one room of a house but that doesn't make it ok. And don't even get me started on betta fish living in a vase with a plant.
As for birds, my Mum breeds Budgies as a hobby. Every budgie we have gotten from a pet store has died within a month of joining the rest of the aviary. However the ones we've gotten from breeders have lived on to be very healthy and easy to breed with. I had the most beautiful, stunning purple budgie who died suddenly within 6 months of us getting him for no apparent reason.
Rodents on the other hand upset me the most. Mostly they are sold live for snake food. (Correct me if I'm wrong but) England have a policy that states no live feeding for reptiles. I'd love to see other countries adopt this policy. Although they have a bad reputation rodents are gorgeous creatures, my pet rat was so incredibly beautiful - completely litter trained, wormed, spayed etc and was such a treasure. Everyone who met him fell in love with him. Now I understand that snakes need to eat, but honestly, feeding them live rodents is very upsetting.
(I'm a HUGE animal lover, it's pretty obvious isn't it!)