If you’re new to building a salt water aquarium, you might not know where to begin when selecting saltwater live coral.  There are a lot of different types of coral to choose from: SPS, LPS, soft coral, and more.  In addition, you need to think of how to light the fish tank, as well as creating the right salinity, alkalinity, and other factors for the water.  Lets take these one at a time. 

First, lets look at the water quality of a salt water fishtank.  This will tell you a lot about the type of fish and coral to put into your fishtank.  The reason why it is easier to get coral and fish from the same region is because the fish and coral need the same salinity and temperature in the water.  A Pacific Ocean fish and a Caribbean fish are going to have much different requirements. 

What this means is that you need to decide on the types of fish you want most and then decide on coral type accordingly.  If a fish requires a certain salinity, find coral that needs the same salinity.  Live coral may live in a different salinity, but it may not be as healthy or live as long.  Soft corals normally need a small amount of nitrates, which could affect certain kinds of animal life—it depends on the type of fish. 

Calcium and alkalinity can promote algae growth.  The idea is not only to maintain a coral reef system, but also to have it grow.  This will affect where you place the corral. If the coral is used to a darker environment with more room to spread out, this should factor into how the coral is placed in the tank.  Generally, SPS and LPS coral (small/large polyped stony coral) need similar properties of salinity, temperature, and darkness in order to thrive. 

Usually people choose the types of fish they want in the fishtank before they choose coral or live rock, but to each his own.  Once you choose one fish, you’ll have to find another compatible fish—both by size and ocean type, possible invertebrates, and then plant and rock life.  When everything is working together, you’ll have created a refined ecosystem that can thrive in a relatively small space.