I don't think salmon change sex to be honest. It seems from the stuff I could find that sex determination for salmon is mostly chromosomal but with divergence at certain temperature during development (or exogenous hormonal influence obviously).
The coolest paper I found while searching was this:
She's awesome. They also did some Pride crafts and while her two co-workers made those Polaroid picture frames with slogans she made a big angler fish hat. Because she thinks they are awesome (she's right).
The aquarium staff hoist the trans flag, and explain that "some fish change gender". The people complaining bring up "gay", but don't seem very well informed about human or aquatic cultures.
That’s a stretch. Social constructs are parts of culture. They can be transmitted person to person and they evolve independently of genetics. Is there any evidence that fish have culture? I doubt it.
Look at how men used to dress in Mozart’s time. That was considered the height of masculine fashion. Today a man would have his masculinity questioned for dressing the same way (or otherwise thought of as strange). Nothing about our genetics could explain such a shift in preferences. There’s no reason Mozart-style fashion couldn’t make a return at some point. That is culture. Fish don’t have it, thus they don’t have gender at all.
Many biologists (myself included) don't anthropomorphize animals because it's impossible to objectively quantify things like "culture". So, my opinion is that some fish change sex, and not their gender (because fish don't have genders, which are human social constructs).
Happy to be corrected if I'm off-base. I'm not an ichthyologist.