Buying the right aquarium fish for your tank is key to the success of your aquarium. When selecting fish, you may not simply be able to pick out the fish that catch your eye in the pet store as not all fish can live in the same environment. Additionally not all fish get along with each other so you will have to be careful to choose the types of fish that are compatible. If all this seems like hard work, don't worry, you will soon become familiar with the types of tropical fish that work well in your tank and even have some favorites that you like to keep. When choosing fish for your aquarium, here's some tips to keep in mind: 1. Fish appearance.

Observe the particular fish you are interested in carefully to make sure he is active and swimming around properly. Make sure his fins are not chewed and he doesn't have any growths or white fuzzy patches. 2. Tank condition. Dealers tanks can have parasites and disease that might not be apparent in your fish right away so you need to observe the other fish in the tank and take a good look at the tank conditions.

Is the tank clean? If not that is an indication that the dealer probably doesn't care for the tanks well. Make sure the other fish in the tank are alert and swimming around actively. Avoid buying a fish from a tank that has dead fish floating in it. Even if your fish appears to be healthy, he could already be infected with something that might not show up until days after you get him home. By then it might be too late and you could risk infecting your other fish. 3.

Water Conditions. The condition of your water is important as well as the number of fish you already have in the tank. If your water condition is poor then adding more fish will just make things worse and endanger the health of all the fish in the tank. Also, you should be careful not to overload your tank with too many fish as this will cause stress on all the fish as well as cause your water quality to degrade. The general rule of thumb for freshwater tropical fish tanks is 1 inch of fish per gallon of water.

If you add too many, you will have to spend more time changing the water and will need really good filtration in order to keep your tank healthy. 4. Water Temperature.

Not all tropical fish like the same temperature water. While most will do well with temps in the mid 70's some do better in cooler waters while others like it on the warm side. 5. Fish size. Before you buy a new fish you might want to find out how big he can be expected to eventually grow. Since your tank can support about 1 inch of fish per gallon, you wouldn't want to put a fish that might grow to 5 inches in your 5 gallon tank or he might be the only one you can have! 6.

The type of fish. Is your new fish aggressive or does he play well with others? Is he OK being the only one of his kind in the tank or will he do better in a school. Make sure you only put fish that will get along in the tank or the more aggressive fish will pick on the others. Also, some fish are territorial and you should only keep one per tank. 7. The food.

Find out what type of food your new fish likes to eat. Most eat flakes, but some like freeze dried worms or other types of food. When you bring home your new fish be sure to also take home some of his favorite dinner.

Lee Dobbins writes for http://www.fish-tank-guide.com where you can learn more about aquarium setup and maintenance as well as choosing fish that are compatible.