How to Choose Fish for a Saltwater Aquarium

Determine the number of fish you can house by the size of your tank. A general rule of thumb is to allow 2 inches of fish per gallon of water.

Buy your fish from a reputable dealer who will back up her product. You want clean fish that won't get each other sick. A good sign that the seller knows what she's talking about is her show tank. Do the fish seem happy? Is it the way you imagine your tank looking when it's complete? If you see dead things floating in the tanks, look elsewhere.

Read about the fish you want. Some have particular needs, whether temperature, chemical, dietary, or compatibility-related.

Begin with just a few inexpensive fish.

Look for damselfish, which are excellent beginner fish. They're tougher than most other marine fishes, tolerating poor water conditions and temperature fluctuations. Be aware that they are fairly aggressive and you should limit your tank to two of them.

Consider the cousin to the damselfish, the clown fish, another attractive starter fish. While they are territorial, they're only aggressive to their own species.

Mollies, although also listed as a freshwater fish, can be an ideal stepping stone between freshwater and saltwater tanks. They are very hardy fish.

Try gobies and blennies, fun little fish with a lot of character. Some eat algae, an added benefit. They do well with most other fish.

Look at crabs and shrimp. They're easy to maintain and reasonably inexpensive. Some might try to eat your smaller fish, so check out the species closely for compatibility before you bring them together. Shrimp need to have iodine added to the water, which is one more thing for you to monitor.

Look into starfish and sea urchins, too. They vary widely in color, size and shape. They help keep the tank clean and are generally easy to keep.

Think hard about anemones, which are particular about water conditions and lighting. They're also expensive.

Avoid angelfish, pipefish, eels, stonefish, clams, seahorses, octopi and jellyfish, as well as the expensive species. These have fairly rigid needs that are likely more than challenging for a new tank owner.