Many years ago the aquarium industry went to central filtration because it was cheaper to set up and maintain one big system that all runs together but they soon found out that if you mix healthy fish with a few sick ones all the fish would soon be sick. So the use of toxic (not safe for humans or animals) chemicals began because of this fundamental flaw. Most central filtrations use a combination of copper, formaldehyde, praziquantel, methylene blue, malachite green, rally and quick ick among several other harsh chemicals on all the fish sick or not to keep the spread of parasites and disease down but just like chemotherapy it has side effects. Most fish end up dead within a few weeks after the sale. It has been done the same way for over 40 years, it did not work then and it is still wrong today but this is what the best experts still teach after all these years as the best way to treat fish to die so more can be sold next month. This international scam runs deep and is a multi-billion dollar kill more for profit replacement type business. The real money is made by selling bottles of snake oil to try and keep them alive or more junk they really don't need because the whole business is one big lie spread by their magazines and sponsors in the industry to keep the real truth in the dark because they make more money if the fish die and need replaced or soon hobbyist would not need them anymore. Brainwashing their victims into killing the real victims so they are mostly dying at one end of the pipeline to assure they can always sell into the other is not sustainable, conservation or education but just pure profit. There is a simple cure to this on purpose cancer plaguing this old system that simply uses true quarantine and No chemicals to stop the spread of disease naturally but that would save lives not money which is their top priority. This outright waste of life for money needs to be upgraded before the only fish left are the ones stuck in their Ark they claim to be building for God while at the same time claiming Sustainability. The only thing sustainable is the death of most fish whether tank bred, raised or wild when put into a central filtration chemical bath found at almost all wholesalers, pet stores and public aquariums.