Biofiltration

So why is Oxygen important in your fish tank?

First and most important, your fish need oxygen just like we do to live. That should be simple enough.

To make it more interesting though, there are several reasons for the presence of oxygen aside from that needed by fishes in an aquarium. The nitrifying bacterial colonies or the so-called good bacteria requires oxygen to convert ammonia to nitrite and nitrite to nitrate. This is one of the reasons why trickle filters are quite popular nowadays as oxygenation is enhanced when used properly (more on this too soon).

Additionally, other unwanted dissolved organic substances are eliminated or transformed into lesser complicated ones (ok, less dangerous) in the presence of oxygen through a chemical process (simplified here).