My only problem with this is that clownfish aren't the best way to demonstrate what I believe they are trying to demonstrate or teach about.....I don't know much about clownfish biology, but I would assume they genetically/physically switch when they go from male to female. This gives them the ability to reproduce as a species. I do know enough about human biology that, whether gay or lesbian, they don't actually change their sex, just they have different sexual preferences. In order to reproduce, humans still need an egg from a genetic female and a sperm from a genetic male. IMO, being heterosexual or homosexual is based on more than just reproduction (for example, love or companionship), where clownfish switching from male to female is based more on reproduction only.
In spite of this, I am all for teaching diversity and acceptance, whether it's religious, race, ethnicity, gender, sexual preference, etc.....I think the whole world, if a bit more tolerant, would be a much more peaceful place where all creatures live in harmony.