In some cases catching fish in the wild is beneficial to the habitat. Case in point; the Cardinal tetra. The annual catch is around 84 million. This number is sustainable, but more importantly, it sustains the local people economically. It is in their best interest to keep the habitat intact to provide a livelihood. Alternatively, rainforest destruction for subsistence farming, is bad for everyone. If the cardinal were to be bred in large numbers in captivity, it could lead to the demise of their habitat, which is the habitat of many other fish and land creature.
As far as Frankenfish, of which the parrot may be the worst example, although angel rams, and ballon fish of various species are right up there, I really hate them as well as the dying and tattooing that is part and parcel of that same industry.