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Siamese Fighting Fish – Betta Splendens


Common name: Siamese Fighting Fish, Japanese Fighting Fish, Samarai Fighting Fish, Chinese Fighting Fish, Mexican fighting Fish

Scientific name: Betta Splendens

Average Adult Fish Size: 5cm / 2 Inches

Place of Origin: The wild fighting fish have much shorter fins than the aquarium ones. When they were bred in Thailand for fighting, colour varieties were developed, but fins were not selected for in the modem sense. The long and fancy fins of the present fighting fish are a comparatively recent development. Fighting fish are bred in many places. A lot of the fighting fish sold in Australia are bred in Singapore for example.

Typical Tank setup: One fighting fish without any other fish can be kept in a quite small tank, provided that it can be kept warm. Fighting fish are usually not an aggressive fish and can be kept in an aquarium with other peaceful fish of a similar size or smaller.

One way of keeping fighting fish is to use one of the Betta containers. These come under several names, but are similar and allow several male fighters to be kept in one aquarium.

Another, similar, way of keeping fighters is to use a breeding tank which floats in an aquarium. Normally these are use for breeding fish such as Guppies, but they can also be used for keeping (but not breeding) Fighting Fish.

There are several other options for keeping fighting fish. There are Duo and a Trio Fighting Fish tank, as well as many types of custom ones. The better ones are big enough to put a small heater into one of the compartments. There is often enough conduction of heat between compartments to keep them all warm enough.

Recommended Minimum Aquarium Capacity: 40 Litres

Compatibility: Generally a fighting fish can be kept with fish as small as neon tetras without trouble. However, the occasional fighting fish may learn to catch neons. I would suggest that in a confined space fighting fish should be by themselve. I know of at least two cases of a fighting fish which has been put in a bag with neons and has learned to eat them. Having learned, the fish is likely to continue to eat neons in an aquarium. Contraray to popular belief, fish have quite good memories.

Fighting fish are slow and have long fins. They are very vulnerable to fish that nip fins. Some of the fish that can be fin nippers and which I would not recommend as companions for fighting fish are Tiger Barbs, Red Eye Tetras, Serpae Tetras, Some Galaxies and Rosy Barbs.

Temperature: 23-28 Deg C / 73-82 Deg F

Water chemistry:  pH 7.1

Feeding: The Fighting fish is sometimes described as a carnivore. In my observation, it is an omnivore with a preference for animal based food. In an aquarium, I recommend that a good quality Betta food be used as the basic diet, and this should be varied with the addition of the occasional feeding of live food like mosquito larvae of daphnia. frozen food like blood worms are also good.

Like most fish, fighting fish are omnivores, in the wild they will eat any animal or vegetable food they can find. They prefer animal foods such as mosquito larvae (wrigglers) daphnia, etc. In an aquarium they will eat all normal types of aquarium foods, but seem to do better on a food designed for them. As with almost any animal a variety of food is welcomed by fighting fish. Do not overfeed!

Sexing: Males are much more colourful than females. Female fighting fish tend to be quite grey and drab.

Breeding: The Siamese fighter is not one of the easiest fish to breed. It is considered to be a medium difficulty fish. Full instructions on breeding this fish would take up much more space than this fact sheet, but since I am frequently asked about breeding this fish, I will attempt to give a very brief description of breeding. Before the fish can breed they need to be in good condition; both the male and the female need to be well fed for sometime beforehand. An increase in temperature will sometimes induce the male to build his nest.

After the male has built his nest, you can attempt to put a female in with him. Watch them! It is not unusual for one of them to attack and try to kill the other. It is not always the male that tries to kill the female.

The fighting fish is a nest breeder. The male builds a nest of bubbles on the surface of the water.

Then he entices a female to go under the nest with him. They wrap their bodies round each other, and the female releases her eggs while the male releases his sperm to fertilise them.

After that the female sinks down in a sort of stupor while the male quickly picks up the eggs in his mouth and put them in the nest. If he has not finished before the female recovers, she starts eating the eggs. This process will be repeated until the female has no eggs left. The male then chases her away. She should be removed.

If there is another female available, in some cases, a male will then induce her to go under the nest as well and he will raise a bunch of fry from the eggs of both females, but you are increasing the danger of problems by having two or more females in while breeding.

The male guards the nest while the eggs hatch. He also guards the newly hatched babies until they are free swimming. After that he will eat them unless he is separated from them.

If you succeed in getting as far as having free swimming baby fighters, now you have the more difficult part. The babies are very small. You need reasonably good eyesight even to see them.

They will need tiny food. In the wild they would be eating things like protozoans. These are single celled organisms usually too small to see without magnification, but much bigger than bacteria. In the aquarium hobby these are usually called infusoria. Some of these will be present in nearly all aquariums, but there will probably not be enough for the babies.

There are ways of making cultures rich in infusoria, but this is a big subject in itself. There are also fry foods made by many companies. Fighting fish will need the finest ones at first.

If you succeed in getting them growing at first, they will soon be big enough to eat larger fry food. At all stages, fighting fish benefit from some live food of suitable size.
At around six weeks old the baby’s accessory breathing organ; the ‘labyrinth’ starts working. At this stage it will be necessary to have a small stream of air from an air stone to break up any surface film because the babies might not be strong enough to penetrate it to get air.

The males and females are normally separated as soon as they can be distinguished, with the males going into containers by themselves.

Additional Information: There are several species in the genus Betta, but the best known and most spectacular is the Siamese Fighting Fish; Betta splendens; the splendid Betta. This fish comes from Thailand and the old name of Thailand was Siam. Other names for this fish are: Japanese Fighting Fish, Samarai Fighting Fish, Chinese Fighting Fish and Mexican fighting Fish. The Cambodian Fighting Fish is a colour variety of this fish. If you put two males together they will usually fight after going through a display. The display seems to be part of the fish’s method of recognising the sex of the other fish. In a limited space like a small aquarium a fight would usually end with one fish dead. In Thailand fish fights are staged with betting on the outcome. This is a traditional sport which is now illegal in Thailand, although this does not mean that it never occurs.