lokittyofcatsguard:

The first one was popular so I made a follow up

Basically, the point of this is that fish produce ammonia in their waste. Ammonia is highly toxic, burns their gills, and will kill them. There are bacteria that convert ammonia into less toxic nitrites, and then there are bacteria that convert those nitrites into even less toxic nitrates, which plants can use. This is how you get them useful bacteria so your fish don’t die slow, painful deaths. 

Also, don’t ever wash your gravel or filter in tap water. Those are what all your good bacteria live in. They don’t live in water, that’s a myth. 

You can potentially bypass the wait by adding filter media or gravel from an established tank. You still have to do all these steps, but you might not have to wait for the bacteria to show up and grow.