Irresponsible hobbyists are to blame by creating demand through ignorant selfishness. Oscars are a great example.That's very fair. Anything like that should not be allowed in. Would be much better for the US saltwater hobby if fish had to pass health inspection by people who actually know what they are looking for before being allowed into the US. The same should be done with freshwater fish and reptiles. Tens of thousands of animals would be saved every year just by preventing sick/diseased/starved animals from being imported. The reptile hobby is the perfect example of this where in just Michigan alone at least 1000 various cheap imports still loaded with ticks and other parasites are for sale at one of the various reptile expos every weekend. 90% of those animals won't live past 30 days in captivity.
Since importing them, they’ve been released into the wild and decimated native ecosystems around the country.
Lake Okeechobee is only one example that had its bass and speckled perch populations eradicated due to irresponsible hobbyists who released their invasive ‘pets’ and destabilized the ecology.