I come across this now and then, and while I appreciate the thinking I feel it is not reflective of reality.
Where it occurs, ornamental fish collection from the natural habitat must (or should) be controlled to prevent threatening the survival of the species. The Project Priaba in Brazil is an excellent example of how critical this actually is. Under this program, local residents make their living from the collection of ornamental fish and it is for them a viable living. If they were not collecting these fish, they would have to look elsewhere for their livelihood, and that almost always means destroying the rainforest for agricultural farming, whether raising cattle or planting crops. So this industry is very important.
At the same time, this project ensures that over-fishing is not a result; in other words, the fish species are not being threatened. So there is really no detriment at all to the collection of wild fish if it is controlled and regulated, and the local individuals benefit and the planet benefits which means we all benefit. You cannot say fairer or wiser than that result.
This unfortunately is not the case in some areas such as much of SE Asia where species have been collected to the point of near-extinction if not full extinction. I don't have the numbers so I just make the point that all situations are not equal.
Most fish are not being raised in captivity, though I say this assuming you mean commercial raising and supply to the hobby.
A number of years ago figures were published showing that of the total export of ornamental fish species from Brazil, 80% of these were one species, the cardinal tetra, and this amounted to roughly 20 million fish of this species. Yet year after year, during the following collection season (this is controlled and regulated for the preservation of the species) the numbers of cardinals in the same waters was just as high. This went on for more than a decade, and may still be the case. The cardinal tetra is believed to be an annual fish in many of its habitats, so if this collecting ceased, the fish would not survive in such numbers anyway.
Another aspect is that wild caught fish of a species are usually hardier and healthier than individuals of that species that are commercially raised over a period of years.