If variety is the spice of life, fish are certainly spicy. From salt-loving Blue Damsels to bottom-dwelling Peppered Cories, they come in countless colors, shapes and sizes and prefer different living environments. But the sheer assortment available in pet stores can be intimidating. Where do you start? And what do you need to know to make the right choices?

First, let's talk size. The number of fish you can keep will depend on the size of your tank. A rule of thumb for freshwater tanks is that each gallon of water will support one inch of fully grown fish. That means a 10 gallon tank should hold no more than five adult fish that are two inches long. Obviously, the bigger the tank, the larger the number or size of the fish you can keep and still ensure their health and happiness.

The next question is whether you should choose freshwater or saltwater fish. For beginners, freshwater varieties are usually best since they're less expensive and easier to keep alive than saltwater fish.

Then decide whether you want a community tank made up of different species of fish or a more specialized tank containing either a school of one species or a single, larger fish that by habit prefers solitude. Many beginners like to start with a community tank, since it gives them the chance to try out several types of fish.

For a community tank, choose your fish based in part on what water level they like to swim in - bottom, middle or top. You will need to mix fish that like the bottom with some that swim around the middle and others that prefer water near the top to make full use of all the swimming space in your tank.

Freshwater Fish

Once you've decided on a freshwater tank, try to steer toward the easier-to-keep varieties to give yourself a greater chance of success. Ideal beginner fish like White Cloud Mountain Minnows, Danios, Rasboras and Barbs are all good choices. All of these species originate from mountain streams in Asia and are related to the carp family. These types will behave as a school when at least six of them live together, making for an interesting swim pattern. White Clouds, in particular, are an undemanding fish that can tolerate temperature ranges colder than most tropical fish, down to 61 degrees F/16 degrees C, and are nicely sized at less than two inches.

If you are looking for fish that tend to swim in the upper water layer, many species of Danios and Rasboras are fairly reliable and easily available. These might create a crowding problem, however, since some species can grow to six inches long. But if you find you have space or if you can find smaller varieties, they're easy to feed, colorful and active.

The many Barb varieties generally swim in the middle to lower water layers. Of these, you may want to stay away from the Tiger Barb, which can be unsociable and is known to nip the fins of other fish. You might consider the Cherry Barb, a pretty, red-orange two-inch-long fish or the Clown Barb, a four-inch long variety. Remember, since the Clown Barb can grow to four inches, you would need at least a 24 gallon tank to keep a school of six. Barbs probably won't school as well as other fish, but they're well worth keeping.

For good bottom-dwellers, consider Corydoras catfish. They're hardy and a good value for the money. The most common variety for a beginner to try is the Peppered Cory. Also look for the Leopard Cory, Skunk Cory, Bronze Cory, Bandit Cory, Spotted Cory and the Panda Cory. Since they swim, burrow and feed on the bottom of the tank, Corys require special sinking food and frozen bloodworms to eat. But you must be careful not to overfeed your Cory, as uneaten food will quickly decay and foul the tank water.

Saltwater Fish

If you think you are ready to try a saltwater tank, you need a word of warning. Although a simple saltwater aquarium is within the realm of possibility for a beginner, saltwater fish tend to have stricter requirements and are less forgiving of mistakes. That means you'll have to keep a closer eye on the tank's temperature, pH, salinity and nitrate content. If you're up for the adventure though, you're in for a treat, and there are fish that make starting out a little easier.

It is widely believed the best beginner saltwater fishes are Damselfishes. They're not expensive, acclimatize well to a new environment and are not finicky eaters. But if you opt for Damselfishes, don't keep more than two since they are notorious for fighting. The best varieties for a saltwater beginner to try are probably Blue or Yellowtailed Damsels. Other good beginner saltwater fish include Blennies and Gobies. Both are small, colorful fish that also help to control algae.

Anemonefishes or Clownfishes as they're more commonly known, are a hardy but territorial species of fish that requires anemones to partner with, which are often more difficult to keep than the fish.

Other reasonably priced saltwater fish that can work for beginners include Surgeons and Tangs. However, both varieties are susceptible to ich or White Spot disease. If you take the plunge and select Surgeons or Tangs, make sure they have plenty of leafy greens, especially if there are no algae growing in your tank for them to eat. It also helps to put some small invertebrates in your aquarium, like the Coral Banded Shrimp. Don't put these in a tank with small fish, however, since the shrimps will have a field day eating them.

If you're a beginner, you should probably avoid aggressive fish like Triggerfish, Groupers and Lionfishes. All three types are expensive to buy and must be fed live shellfish and other marine animals. It is possible to feed them less expensive goldfish, but this can result in their developing liver failure. Until you gain the experience and skill to successfully keep more expensive fish, it's best to keep it simple.

Of course you're going to be tempted by the beautiful Angelfishes, Butterflyfishes, Batfishes and all the other gloriously colored saltwater fish. But again, resist the temptation. Be resolute and stick to the easier varieties. Once you get the hang of caring for your new pets, it will be easier to research and find other species that are compatible with those you already have.

Make Changes Gradually

Whatever aquarium environment you choose, build up your fish collection slowly, taking into account the compatibility and acclimatizing issues of the new fish you introduce. In nature, an aquatic environment evolves slowly. The unhurried pace and peace inherent to any stream or ocean are things that make this hobby so soothing and relaxing. As long as you give your tank the gifts of time and patience, it will reward you with an abundance of enjoyment.