Aquarium Water Chemistry

Tropical aquarium fish inhabit many different bodies of water across the globe and each body of water varies in chemical composition.

Over millions of years fish have evolved to adapt to their natural surroundings and for a fish to be happy and healthy in an aquarium, the water’s chemical composition must be similar to that of the their natural habitat.

There are two approaches to water chemistry; one can keep fish suited to the local tap water and we recommend this option to beginners – your local retailer should be able to advise you which species are “hardy”.

Alternatively, one can modify the water’s chemistry but be aware, modifying the water can be expensive, time consuming and there is always the possibility of error.

The pages below are intended to provide an understanding of water chemistry and will endeavour to explain in simple terms the meaning of each aspect, how it affects the fish and how you as a hobbyist can control it.

Environmental ParametersCompounds Of Importance To The AquaristWater Sources & Cycles
Aeration (Oxygenation) AmmoniaThe Nitrogen Cycle
HardnessNitriteThe Water Cycle
OsmosisNitrateNatural Water Sources
pHCarbon DioxideTap Water