Set up a Five Gallon Fish Tank

Keeping small fish can be fun and rewarding, and if you follow these simple steps, your fish will thrive!

Steps

Put five gallons of water in a container or multiple containers and let it rest for a day or two.
Add the background, substrate and decorations to your five gallon tank. Try to keep the decorations natural or at least natural looking. Driftwood is common and looks good.
Pour half of the the water you previously prepared in the tank. Use a colander or a plate so you don't ruin your arrangement of decorations.
Install the filter, heater, and air pump. Some fish do not require a heater, but filters are necessary to keep your tank clean.
Arrange and place your live plants.
Add the rest of the water to your tank.
Add several drops of conditioner (water conditioner, not hair conditioner). Follow the directions on the bottle as to how many drops are needed.
Let the tank cycle for at least two weeks and occasionally add some fish food in it. Cycling a tank is important because it lets helpful bacteria form. That bacteria will later dissolve the ammonia from the fish feces.

Buy the fish! You can also get snails, shrimp or frogs. Don't add them right away. If they're in a bag, let it float in the tank's water for about ten minutes. Mix some of the water in the bag with the water in the tank. Do this every few minutes, and eventually let the fish out of the bag so they can explore their new home!
Feed your fish twice a day. Don't add too much. however. Surprisingly, overfeeding your fish is worse than underfeeding them.

Keep in mind the fish's needs and how they will get along.
A tropical fish's recommended temperature is 76-82F. Try to keep it the closest you can to that temperature.
Research the fish that you are going to buy, and make sure they are able to live in a five gallon tank. Recommended fish are smaller live bearers, such as guppies and platies.You can also put smaller tetra species, danios, or white cloud mountain minnows in your tank. If you don't want a lot of fish, a betta fish is a great choice. You can put only one in a tank, however, because they are aggressive fish and might even fight each other to the death. Appropriate bottom-dwelling fish are otocinclus and smaller corydoras species (such as the dwarf and the pygmy cory). Shrimp are a great addition to your tank.
Some fish may not need an air pump if you have a hanging filter that creates enough bubbles.

Keep in mind that some fish have different temperature requirements.
Many livebearers will rapidly reproduce. It is important to keep this in mind when buying your fish; if you cannot support the large amount of baby fish then you should buy only females or only males. Females of certain species are less colorful, but they are also less likely to get into conflicts.
Make sure your wash off your decorations before you put them into your tank. DON'T clean them off with any cleaning agent such as soap or bleach. It can be very harmful to your fish.
Don't combine aggressive fish and other fish. Doing so will not result in a pretty situation!
Don't stock your tank with fish that will grow large. It is both a torture for the fish and doesn't look good. Inappropriate species include: plecos, most cyprinids (especially goldfish!), cichlids and loaches, bigger species of livebearers, tetras and corydoras.
Don't get fish that are drastically different in size. If the fish is to small, it will most likely be eaten by another bigger fish. Remember; if a fish is small enough to fit into another fish's mouth, it will most likely be eaten.