Many different tetra species are popular in aquariums, including the well-known Neon tetra (Paracheirodon innesi) and Cardinal tetra (Paracheirodon axelrodi), as well as rarer species such as the Congo tetra (Micralestes interruptus) and Serpae tetra (Hyphessobrycon eques). All tetras are found in a family named Characidae in the order Characiformes. They are comparatively small fishes and many species are popular due to their striking coloration. The Neon tetra is one of the most popular fish species among novice aquarists since it is sturdy, adaptable and will stay smaller than 2 inches (5 centimetres). It is also beautiful and will add colour to the aquarium with its vibrant blue and red colouration.

Using a dark substrate is a way of making this fish look even more stunning. Another reason behind the popularity of this fish is its peaceful and non-aggressive temperament that makes it suitable in any peaceful community aquariums. The Neon tetra should never be kept alone since it is a schooling fish.

Get at least ten Neon tetras, preferably even more. They will also look much more stunning when they can form a big school in the aquarium, and since they feel less stressed and frightened in a group they will spend more time out in the open. The Neon tetra is a South American Tetra native to warm rivers in Peru, Colombia and Brazil. The water temperature in your aquarium should therefore be in the 22-25 degrees C range if you want your Neon tetras to thrive.

Your Neon tetras will do better in a planted aquarium than in a barren tank. Sturdy plant species like Java fern can usually be kept even by very inexperienced aquarists. Artificial plants are another alternative that will provide your Neon tetras with a sense of security. Ideally use both substrate plants and floating plants in your Tetra aquarium. The floating plants will dim the aquarium light and thereby make the fish feel safer. As mentioned above, it is an adaptable fish and it can live in acidic as well as slightly alkaline water, from pH 5.

5 to pH 7.5. Feed this fish a high quality flake food suitable for tetras, and make sure not to over feed your fish since obesity will seriously harm their health. If you want to try a more unusual tetra you can for instance choose the Congo tetra.

The Congo tetra is not as commonly known as the extremely popular Neon tetra and is usually kept by more experienced aquarists. The Congo tetra will require a more active keeper than the Neon tetra; the water must for instance be changed very often since the Congo tetra is sensitive to high levels of soluble waste. The Congo tetra will do best in an aquarium with strong circulation. Keep the water temperature from 23 to 26 C and the pH in the 6.

0 to 7.5 range. Even though your Congo tetra will tolerate a pH above 7.0, it is recommended to keep the water slightly acidic, since this will make the Congo tetra less sensitive. This tetra is native to the Zaire River basin where the water is quite soft, but it can adapt to harder waters in captivity. Always keep a school of at least five Congo tetras together.

Allen Jesson writes for several sites including two sites that specialize in salt water and fresh water aquariums and the aquarium site and Seapets, a leading source for aquariums and fish tanks.