Betta Fish (Betta splendens)
Care & Breeding Notes
Also known as the Siamese fighting fish, bettas belong to a group of species equipped with a unique respiratory adaptation called the labyrinth organ. This highly folded, lung‑like structure allows them to breathe atmospheric air directly, an ability that is vital for survival in their native environments where dissolved oxygen is often extremely low. By rising to the water’s surface to gulp air, bettas can thrive in the shallow, stagnant, oxygen‑poor waters of Southeast Asia, the region they originate from.
Natural Habitat
Betta fish, particularly Betta splendens (Siamese fighting fish), are native to the Mekong Basin and surrounding regions, including Thailand, Cambodia, Laos, Vietnam, Malaysia, and parts of Indonesia. These areas are tropical, with temperatures ranging from about 50°F in cooler periods to over 104°F in summer, and they experience seasonal rainfall and monsoons that influence water levels and habitat conditions.
In the wild, bettas thrive in warm, shallow waters typically around 3 feet deep. The water is often slow-moving or stagnant, such as in rice paddies, small ponds, ditches, and canals. Water parameters vary: pH ranges from slightly acidic to neutral (6.5–7.0), and hardness can range from very soft to slightly brackish. Dense aquatic vegetation provides shelter, breeding sites, and natural barriers for territorial behaviour.
Size & Lifespan
Adult size: ~7.5 cm (3")
Lifespan: 2-4 years in captivity
Temperament
Bettas are tough fish and called “fighting fish” for a reason. Male bettas are particularly aggressive, especially towards other males or fish that look like other bettas. Females are more docile, but can still display aggression. You’ll need to choose your bettas tank mates very carefully.
Male Bettas
Males betas are more territorial and aggressive than females. Here are some things to consider with a male betta fish:
Never keep two males together, even in a large Betta tank. They will likely fight to the death.
- Brightly coloured fish with long fins can be mistaken for another male betta, leading to your betta attacking the fish.
- Even holding a mirror or a picture of another male betta up to the tank can cause a male betta to become aggressive towards the image, thinking that it’s another betta.
- Male bettas are solitary, and do very well in a tank by themselves.
A male betta will build a bubble nest for potential offspring, even if there are no females around.
Female Bettas
Female Bettas tend to be less aggressive, but you should still be careful. Territorial behaviour does exist in females, and they may even fight with each other.
Female bettas can safely be kept in groups of five or more, known as a sorority.
Female bettas are less colourful than males and less territorial.
If you are keeping a sorority, you should start with bettas of a similar age.
Sonorities still need plenty of space, to prevent territorial displays and aggression.
Both male and female bettas have unique personalities, and not every female will be suitable for sorority life.
Varieties (Tail Shape)
Betta fish can be categorised by tail and fin shape, colour, and pattern. Just about every colour and pattern is available in most styles of tail shape.
- Veil tail: is the most common type of betta fish. Its fins are long and sleek, swooping downward
- Combtail: a combtail betta is a little fancier than the traditional veiltail. Its tail and fins taper to points, giving a ragged “comb” appearance.
- Crowntail: are similar to combtails, with a more fringed edge to their fins and tails. The main difference between crowntails and combtails is that a crowntail’s fin webbing should reach at least two-thirds of the way down its fins
- Halfmoon: are outstandingly beautiful, with majestic fins even when compared to regular betta fish. Their famous “halfmoon” tail fins fan out in a full 180 degrees, creating a half-circle shape.
- Double tail: just as its name implies, a double tail betta has two distinct and separate tail fins, giving it a unique shape.
- Delta: a delta betta is a more unusual type of betta, with its fins narrowing at the top of its body and fanning out at the tail fins. Deltas look similar to halfmoons, but their tails don’t quite reach the half-circle shape.
Varieties (Colour Patterns)
Each
colour encompasses a range of shades and hues, leading to a
completely unique colour or combination of colours.
Solid
coloured bettas do exist, but they tend to be rarer than patterned
bettas. Some common patterns you might encounter are:
- Marbled: a marbled betta has half-light colours and half-dark colours on its body and fins, ideally with a noticeable contrast between the colours.
- Grizzled: a grizzled appearance creates an ethereal, iridescent effect on the bettas’ fins and body, with delicate strokes of colour, like a paintbrush. Like the marbled betta, the ideal ratio of light to dark colours should be 50:50.
- Butterfly: similar to a bi-coloured betta, butterfly bettas have one colour on their bodies and another on their fins. The body colour should seep into the fins, leaving a definite line on the fins.
- Bi-color: bi-coloured bettas are very common, and are available in most varieties and combinations of colour. The body of a bi-coloured betta is one colour, and the fins another.
Aquarium Setup
Bigger is better when it comes to tank size and they thrive in large tanks, with good water quality, regular cleaning, and plenty of decorations. A gentle air pump and an efficient water filter will keep the tank clean and in good condition. The minimum tank size for a single betta is two gallons. Tiny, decorative fish bowls are not suitable for bettas — or indeed any fish.
Water Parameters
Temperature: Bettas prefer warmer water, ideally between 72–86°F / 22–30°C
- pH: 6.5–7.0
- KH: 5–20°
- My current setup: 26.5°C, pH 6.8, KH 5
Bettas adapt well to a wide range of conditions. Planted and floating plants, botanicals and driftwood make excellent décor and help replicate their natural environment.
Diet
Wild bettas are carnivorous, feeding on insects, insect larvae, zooplankton, and small crustaceans. The abundance of small prey in rice paddies and shallow ponds supports their dietary needs and contributes to their survival in these environments.
These fish benefit from a varied diet. Mine receive a rotation of:
Micro granules
- Flake food
- Daphnia
- Baby Brine Shrimp
- Bloodworms (not too much)
Breeding Project
Male and female bettas should only be put together for breeding purposes, as the males will become aggressive towards the females.
Here’s what you should look for in suitable breeding bettas :
Less than a year old — fertility drops after the bettas first year of life
- Bright, vibrant colours in a male — this is most likely to attract females
- High energy levels in a female
- Excellent overall health in both the male and female betta
Regular water changes will mimic the rainy season in the bettas’ natural habitat, indicating that it’s time for the bettas to start breeding. 25% water changes twice weekly will do this. If possible freshly collected rain water.
Feed your bettas more frequently but in smaller amounts. Keeping the breeding tank bare and still, without using a strong air pump and filter, will help the fish to focus.
When you add the bettas to your tank together, keep them separate at first, with a clear plastic divider.
The male betta should start building his bubble nest. Once the nest is ready, and you’re sure the female is interested, you can put the two fish together. Take the female betta out of the tank if you think she’s in danger.
After successful mating, the male betta will start collecting the eggs in the tank and taking them to the bubble nest. You should take the female betta out of the tank, then leave the male to take care of the eggs and the fry, once they hatch.
Don’t feed your male while you wait for the eggs to hatch — it’s not unheard of for a first-time father to eat his own eggs.
