One of the biggest mistakes beginners often make is to choose the wrong fish. Just because it looks nice, it doesn't mean it wants to live with you. The fishes in the stores are babies - that cute little Oscar that is the size of your thumb today will be a one foot long cricket-eater a year from now and want a 75 gallon tank all to itself! Are you sure that's who you want to adopt? Always always always RESEARCH the fish you like BEFORE you buy it! Species have unique needs - some need to be alone and some need to school with their own kind. Some fish need live food and some will do well on flakes. Some fish need caves to hide in and some need live plants. Research before you buy, and make sure you can give that animal a satisfactory home.
The term "Community Fish" is used to describe species that can share the same tank. Be aware, however, that an individual fish might have an aggressive or frightened personality, so you should find aquarium stores that will take your fish back if they don't get along. An aggressive individual can be less of a problem if it is kept in a large tank with a lot of other fish it can chase around. With too few tank mates, it can harass those fish into disease and despair. Like all animals, fish have special needs for territory - they will fight over space and shelter. Know what they need, and be sure you have enough for each fish. Also remember that no matter how nice they are, most big fish will eat your small fish! When you research a fish, it is a good idea to know the scientific name for that species, because common names are sometimes confusing - two different fish might have the same common name, or the store might be calling it something different than what it is.
Some Small, Commonly Sold, Community Fish Are...
Angelfish; Pterophyllum scalare; eats floating food like flakes or fruit flies, low pH. 15cm.
Catfish; Corydoras panda or other Corydoras, bottom feeder, likes to school. 4-8cm, depending on species.
The Livebearers: guppies, swordtails, platys: a guppy's fancy tail is sometimes attacked by more aggressive fish. These fish have live babies and lots of them! Make sure you know what you are going to do with them - I keep an angelfish with my guppies to eat the extra babies - the live food is great for her!
Rosy Barbs; Puntius conchonius; my personal favorite. Males have black tips on their fins and are bright red when healthy and excited. Females are more chubby and like to lay eggs at the base of plants (which gives them all something good to eat!). 15cm.
Harlequin Rasbora; Rasbora heteromorpha; small and pretty, mid water, needs to school.
Zebra Danios; Brachydanio rerio; fast: they like to chase each other. 5cm.
White Cloud Mountain Minnow; Tanichthys albonubes; name means "Tan's fish." The red fins have white tips - pretty little fish. First discovered in China by a boy named Tan. Does well in cool water - can be kept without a heater. Mine live with the goldfish. 4cm.
Blue Gourami; Trichogaster trichopterus; eats flakes or flies from the surface. Males can sometimes be territorial. 15cm.
Ottos, an algae eater. Otocinclus affinis; vegetarian, eats algae, which helps to keep the tank looking clean. They look cute perching on leaves and rocks. Likes the company of it's own kind. 5cm.
Neon Tetra; Paracheirodon innesi; beautiful little fish, neon blue stripe on red and white body. Mid water, likes to school with other neons. Delicate, more sensitive to water quality problems.4cm.
Goldfish; Carassius auratus; not usually considered a "community fish" because it prefers cooler water than tropical fish. DON'T keep one in a bowl - they need more water than that, and they dirty the water faster than other fish do. The cheap goldfish sold as live food are Comets. They get large - be ready to put them in a pond in your yard. NEVER release any unwanted fish into the wild. Non-native species often hurt the environment.
Oscar; Astronotus ocellatus; of the fish mentioned here, the popular Oscar is the only one I have never owned, although I hear they will love you like the family dog. Too many stores sell these to people who don't know what they are buying. There is a reason I have never owned an Oscar: it will grow (quickly!) to become 35cm and need 200 liters of water. That is a fish that is more than 14 inches long, in a tank that is more than 50 US gallons! Any fish you put with it will be eaten. Consult someone who owns an Oscar before you buy one. Many of these fish are homeless, because they were sold as community fish. THEY ARE NOT COMMUNITY FISH. If you want one, it is a good idea to try to adopt one that has outgrown its original owner. Ask around.
There are many great community fish. For other types of fish, including aggressive species, make sure you know how to keep them BEFORE you buy them. On my LINKS page, you will find links to sites that can help you research any fish you fancy.
FILTERS AND STUFF
THE NITROGEN CYCLE
DISEASES AND MEDICATIONS
PLANTS AND ALGAE