It would actually be an interesting study in human behaviour and association that the story of Nemo was theft for a pet; and yet so many people wanted a Nemo for a pet which relied upon theft for a pet.
Ironically they near all became the "baddy" in the first film.
I wonder if this is because many failed to make the connections because at the end of the day the story was a film not reality; or because most people see fish in pet stores and assume they are captive bred and because they are not involved in the harvesting of the fish they have no idea of what really goes on.
Indeed I suspect the latter might be more true; most people don't question where pet-shops get their stock. And if asked many won't say "We harvest wild stock" they'll likely say "we use approved dealers and breeders" or some such which allows them to answer without giving any specific information out.
In the end it really depends on the cinema groups; both the production studio and the cinema groups that buy the film to show. If the former don't want to an independant film could be made by interested parties; though it might be a devil of a job actually getting it onto the big screens.
This is the kind of thing that can sometimes work its way into the "extended super deluxe" edition DVD release; but a lot of people never watch the documentaries that go with them
Darla is truly the most evil Disney villain.
This kind of thing is actually pretty common, a popular movie features an animal, causing an increased public interest in the species, and this unfortunately results in a lot of people getting pets they aren't qualified to handle. (this even happened with owls and Harry Potter, apparently) One well-documented instance of this is with dalmatians and the live-action 101 Dalmatians. Dalmatians aren't exactly a beginner breed, so many of the dogs were abandoned. Plus, to meet the demand, puppy mills just kept breeding dogs with little regard to health or welfare.
A big part of this issue is that a lot of people unfortunately don't do their research when they decide to get a pet, whether or not a movie influenced them. Even a beginner saltwater aquarium (I've heard that clownfish are pretty good for such aquariums) is more work and money than most people are willing to put in. Most people are used to treating fish in general as throwaway pets, so even after hearing the costs I can picture a lot of people ignoring those warnings. ("I kept a goldfish in a one gallon tank and it lived for a whole year!")
And, as you say, most people aren't aware of the environmental impact. Now, these days, it's pretty easy to find a captive bred clownfish, but the same can't be said for the blue tang. I wonder if a PSA would be more effective if it focused on the environmental stuff rather than the pet maintenance stuff, since I feel like people would be more likely to ignore the latter. Though, still, there will always be people who will still get the pet even after knowing it's bad for the animal. Some people care more about seeing or owning the animal than its welfare, so they support and do things they know are harmful.
