Instructions
Check to make sure that the fish you will be keeping together have similar requirements for temperature and water parameters.
Check a compatibility chart published by website such as Live Aquaria (see Resources). Remember that each fish is an individual, and just because species are listed as compatible doesn't mean every fish will get along.
Consider the sizes of the fish. Don't try and keep large predatory fish with smaller fish, or the smaller tankmates may end up as dinner.
Contact your local fish store if you have doubts or questions. There are many shops that specialize in saltwater aquariums with knowledgeable experts who can give you advice.
How to Check the Compatibility of Tropical Fish for a Saltwater Tank
When considering what fish to add to your marine aquarium, you need to give careful consideration to whether the fish will be compatible. On top of environmental factors such as temperature, you need to consider the temperaments of your fish. An aggressive fish introduced into a tank full of peaceful inhabitants can wreak havoc. A peaceful fish introduced into a tank full of aggressive fish might be attacked or die from the stress of being constantly harassed.