Keeping coral tanks is a hobby for me. I don't sell anything and I am sure I am not going to replenish the ocean with any of my corals. Reef tanks can put a spotlight on the problems with natural reefs, but is not going to change the balance of the issues with global warming or habitat destruction has on reefs. Nature really does not care what people think. There will be life on this planet long after we try to destroy Earth (with or without our species). I actually do have some corals that came in on live rock that is off limits to regular collection. I do not know of any corals that are kept in tanks that are endangered species. I find that science is misdirected when we know more about Mars than we do about the oceans on Earth. Coral reefs are only a sliver of ecosystems in the oceans, but like pretty animals, they get more attention than stuff that "grows in the mud". We need a holistic view of Earth, then we can actually live "with" nature instead of worrying about how we are going to kill the Earth. So, after all this rambling, I don't believe we are helping the environment by keeping corals in tanks. I do think that if all wild corals are off limits, there is enough corals in existing aquariums to supply the need. I love my pretty corals, but they are for my enjoyment, nothing more.