Now you have your saltwater aquarium tank all set up. All you need are some finny friends to keep you company. But which fish are the right ones, and how many should you acquire? The answer to the second question is simple math. You can acquire three inches of fish for every ten gallons of water. So the species of fish and factoring in how fast they grow are calculations you should make before you go to the pet store and make acquisitions.

The second factor is time in between acquisitions. You don't want to throw five new fish into your tank because it will destroy the equilibrium of your tank's current bio system. Even in the beginning, you only want to put one or two new fish in your tank at a time, adding new ones at two to three week intervals until you are satisfied.

The third factor is mood. You don't want anti-social or territorial fish in your tank because they will take over that cute little castle at the bottom of your tank and forge swords in it. That is to say, they will kill your other fish! Also important is that fish species grow at different intervals. Large fish usually eat small fish, so if you have species that grow very large and are predatory and others that don't, expect your small ones to become food. Also, just because a fish species is not generally aggressive, keep in mind that some fish are mavericks and are either territorial or aggressive despite normal species tendencies. Make sure you ask your dealer before acquiring a fish what its disposition is or you may be adding an evil fish that will make your nice friendly fish lives a nightmare experience.

Diet is another factor that you should take into consideration. If you are not going to have coral in your saltwater aquarium, then you shouldn't get coral eating fish. There are some species that are naturally hungrier than others, and providing for their special dietary needs may cause a disruption in the balance of food you need to add to the tank, leading to the early demise of other fish in your tank, or to that species if its food is taken by others. This can also lead to fish becoming defensive towards one another, which leads to war!

Set-up Type compatibility is also a key factor in deciding on your fish and other tank livestock. There are some fish suited for fish only tanks, some for fish only with live rock, or reef tank system and you are going to want to ensure that you acquire the right species to survive with your setup, or your fish will either not survive or become defensive, and go to war!

The bottom line here is organization. Working with your local pet dealer and doing your research to understand what fish go together and what fish don't, along with understanding the correct progression for increasing the amount of fish in your saltwater tank will all go a long way towards providing both you and the fish a peaceful habitat for you to enjoy and for the fish to live in.