Siamese Fighting Fish

The Betta or Siamese Fighting Fish Betta splendens is a very beautiful and vies with the highly favored Guppy Poecilia reticulata and the familiar Goldfish Carassius auratus for the title of best known fish. They are also one of the oldest known freshwater fish to be kept in aquariums. They were collected before the 19th century in both Thailand and Malaysia. The Goldfish and their close cousin, the Paradise Fish Macropodus operculari, are perhaps the only species that have a longer history in the trade.
These fish are well known and greatly appreciated for their gorgeous appearance, interesting behaviors, and simple space requirements. Dubbed "the Jewel of the Orient", they have been selectively bred across generations. Through selective breeding quite a number of different varieties have been developed sporting gorgeous colors, color patterns, and incredible fins. Other common names they are known by are Split-Tailed Betta and Libby Betta.
In their wild form, the Siamese Fighting Fish is dull green and brown in color and it has a stout elongated body with short rounded fins. The name "fighting fish" comes from the fact that males will most often fight each other until either one or both of them are dead. Short-finned males have long been bred in Thailand for fighting purposes, though in this sport the combatants are usually separated before a fatal outcome. They are ferocious fighters, yet interesting behaviors occur during combat. If one of them goes to the surface for air they will pause the conflict, and the other will not take advantage of its rival during this temporary helplessness. Also if there is a third male, it will wait its turn to fight the victor rather than joining in the fray between the other two.
The popular Betta, as it is known in the United States, is an equally combative Siamese Fighting Fish. Wild male Betta's have short rounded fins and the beautiful specimens available in pet stores today have been developed from this wild variety. Their fins can be short to very long and flowing. The most commonly available are the Veil Tail Bettas but there are many others. Fancy Bettas range from those with a double tail fin to those  with a crescent or half moon tail fin, and others with a crown design to all their fins. Only the male has the long fins though. The female's fins will be shorter and females are generally more drab in color. When agitated both sexes will flare out their gills and fins making an impressive display, These captive bred aquarium specimens don't lend themselves to a combative type of sport however. Their long flowing fins are very delicate and will actually fray if even the movement of the water is too fast.
Bettas are a great fish for a beginning aquarium enthusiast or for someone who wants minimal space and upkeep, but still wishes to enjoy a beautiful fish. Their needs are minimal in comparison to other species. They are quite disease resistant, very resilient, readily available, and inexpensive. They are hardy and will adapt to most aquarium conditions and their special 'labyrinth organ' enables them to survive in oxygen-depleted waters. Because of this they can survive in smaller spaces. A minimum sized aquarium for a single specimen would be 3 gallons if kept in a warm room, and with regular maintenance. They will do best however in a larger aquarium, a 10 gallon aquarium is recommended, and also allows room for other tankmates.
These are good community fish as long as the selection of tankmates is made with care. During and after nest building, the male is extremely aggressive and will regard anything that even remotely resembles a fish as a rival. This is especially true if it is similar looking fish (even a female), or a colorful fish. For this reason you can only keep one male per tank and you must select its companions carefully. They do fine in a community tank with fish that are very peaceful, similar in size, and more drab in color. Females can be kept in groups but males should be kept singly. Males can be kept in pairs or with several females if the tank is large enough and there's lots of hiding places for the females.