I think the exploration of new species to be introduced into the aquarium market should be banned and I think all marine fish should be banned. The only fish we should keep are those that can be bred in aquariums, which will stop most of the large fish being kept as well.
Actually, without captive/ domesticated animals/ fish, there is a good chance every species in the oceans will become extinct in the very near future. This also applies to freshwater rivers, creeks and streams, where fishes and other aquatic organisms are going to become extinct in the wild due to human interference and climate change. Then the only creatures left will be those we keep and breed in aquariums or ponds.
Many smaller species of marine fish are being bred in captivity, as are corals, albeit corals in aquariums are usually propagated by fragments (aka frags), not through the release of gametes by individual coral polyps. And many corals are threatened with extinction due to climate change and warming oceans.
Marine shrimp are relatively easy to breed but hard to metamorphis, however if people put some effort and research into it, this should be easy to overcome.
Before banning marine fishes completely, think about how long freshwater fishes have been kept. They have been kept in glass aquariums and bowls for over 100 years, and people are just now starting to provide more natural settings for these types of fish. Some have been kept for much longer in ponds (goldfish). Saltwater fishes and corals have only been kept during the last 60 years and even then, they didn't get kept by many people until the late 1980s. Marine fish keeping has evolved a huge amount in the last 30 years and in some ways, coral tanks are actually well ahead of most freshwater tanks in terms of natural environments and stabile water conditions.
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If aquarium fishes are banned, there will be a major impact on most country's economy because 1 in 4 households in most modern cities, has an aquarium or pond. Get rid of fish keeping and you get rid of billions of dollars going into the economy and that is going to cause more than a few ripples in the government coffers.
I am all for regulating the fish industry. They could start with a blanket ban on deformed fishes like the balloon fishes. They could ban the keeping of fishes that grow bigger than 12 inches. The only exceptions being for public aquaria and zoos, who presumably would have suitable sized facilities to house monster fishes. Or if people have a suitable sized pond or aquarium for these fishes, but they would have to provide proof to a government department that would come and view the pond/ tank and confirm it is suitable.
We can have fish and care for them. And fish keepers worldwide will be the last saviour of fishes when they become extinct in the wild. It has happened with birds. The Gouldian finch was about to become extinct in the wild but was saved by captive breeding programs. The same thing will have to be done with fishes and all other animals, birds, reptiles and insects on this planet. Otherwise there will be nothing left.
Regulating something like the aquarium industry needs to be done on multiple levels and include things like banning the sale of deformed organisms, protecting natural environments so individual species can survive in their natural habitat, and encouraging good ethical care of our pets. Unless all of these are done, banning one section is not going to do a damn thing except annoy a whole lot of people, and then we can all sit back and watch everything in the rivers disappear from history because of stupid policies.