Tropical Fish Site

Profiles Reviews Guides for Tropical and Marine

What Is The Purpose Of Carbon In Fish Tank Filters

If you have ever used any kind of medication or treatment in your fish tank aquarium then you may have noticed that the majority of them say to remove the carbon from your filter before you use the treatment. This gets the mind wondering what the point of having carbon in a fish tank filter in the first place is.


Well, in short it is the lazy persons way to treat aquarium water. It removes chemicals and dissolved organics along with medications, but it shoudl not be seen as a substitute for frequent partial water changes. With frequent partial water changes (a good start is 20%) the use of carbon in an aquarium filter is unnecessary accept after completing a course of medication as carbon will readily remove most fish medications.

Carbon is also good to have on hand in case of a “fish emergency”. I’ve known cases where a non-fish keeping guest or member of the family has spilled something toxic into an aquarium on accident (on purpose?!). Another problem is someone spraying aerosols near the aquarium. Bug sprays, air fresheners, and household cleaners can be lethal to aquarium fish! If carbon is introduced into the filtration system of the aquarium quickly enough, and a course of water changes are also done, it will reduce the possibly lethal substance enough to give the fish a fair chance of survival. Carbon should be in every fish keepers “first aid kit” for their fish!