Sometimes it’s just easier to look at a chart and move on.  For more detail about a compatibility component visit the compatibility discussions.  These charts are for freshwater and saltwater fish providing a summary of the compatibility information and more.

Each chart can be enlarged and zoomed into to see a specific fish or compatibility value.

The Water Hardness Compatibility chart examines the water hardness fish prefer.  Many fish have specific biological requirements for higher calcium and magnesium levels in their natural habitat.  Some, on the other hand, are better suited to lower concentrations.  The amounts of these chemicals in the water can influence breeding and reproduction.

Compatibility is determined by similar types of water hardness represented using dGH as the measurement scale.

To create this chart the dGH preference was established for each species of fish.

Then a compatibility score was assigned that represents the species preference for dGH.

• Dark Green: Highly Compatible (Score: 3)
• Medium Green: Compatible (Score: 2)
• Light Green: Slightly Compatible (Score: 1)

Note: While there is a significant range of dGH that a fish can exist within, There is a preference level that should be observed.  This chart shows the preference between fish species and does not show the value of dGH that each fish preferred.