Candy Koi Female Plakat Betta (Betta splendens)

Choose a candy koi female betta for a planted tropical aquarium

The candy koi female betta is a short-finned female Siamese fighting fish, Betta splendens, with a pale, pearly body splashed in red, orange and white, dark blotches along the back and flanks, and patches of metallic blue scales towards the tail. Her fins are short and rounded, red and white with blue streaks. This combination of a plakat fin shape and a multicoloured koi pattern makes a bright, active fish for a heated, planted aquarium.

Bettas are labyrinth fish: as well as gills, they have an organ that lets them breathe air at the surface, which suits the still, warm, sometimes oxygen-poor waters they come from. Seriously Fish places the wild species in central Thailand, from Chiang Rai province south to Surat Thani and Phang Nga, in rice paddies, swamps, ditches, streams and ponds, often shaded by plants. FishBase describes its range as the Mekong basin and lists the wild species as Vulnerable on the IUCN Red List (assessed in 2011).

Decode the name

"Koi" and "candy" are names used by breeders and shops, not formal standards, so different sellers may draw the line between them differently. Compare her with our Koi Plakat Female Betta, the Galaxy Plakat Female Betta and the long-finned Halfmoon Koi Female Betta, or browse all our betta fish, the betta and labyrinth fish category and the female betta category.

Know what you receive

One purchase supplies one live female candy koi plakat betta, graded medium-large. She is a young adult or near-adult fish; the species reaches about 6–7 cm, with OATA giving about 7 cm, Seriously Fish 70 mm standard length and FishBase 6.5 cm total length. The photographs show the colour form, not your individual fish: every koi betta carries its own arrangement of colours.

Expect a pattern that can move

Breeders widely report that koi and other marble-type bettas keep changing their pattern as they mature, with patches spreading, shrinking or shifting colour. We have not found a scientific study that identifies the genes behind this, so treat it as hobby experience rather than proven fact, and enjoy the pattern as it develops. Colour also responds to mood: a settled, well-fed betta is brighter than a stressed one.

Ornamental bettas have a long and mixed history. A genomic study by Kwon and colleagues (2022) found reports of bettas being kept in Thailand from as early as the 14th century and estimated that domestication began around 700 generations ago; 76% of the ornamental bettas they sampled carried ancestry from other Betta species. Seriously Fish notes crosses with B. imbellis, B. smaragdina and B. mahachaiensis.

Short-finned males and females can look alike. Seriously Fish notes that some commercial breeders reportedly sell very short-finned males as females, and males are usually the more colourful sex with longer fins. If you are building a group of females, watch for a fish that builds bubble nests at the surface, the job of a male, and keep a spare aquarium ready. Read our female betta fish guide and our delivery and Live Arrival Guarantee details before you order.

Plan the aquarium around one female or a group

A betta is small, but it still needs a filtered, heated aquarium; Seriously Fish says the species should not be kept in tiny aquaria or jars. For a single betta it recommends a base of at least 45 × 30 cm, about 41 litres. OATA gives a minimum of 20 litres for a single male and at least 60 litres for a group of females, which should number at least four, and more is better.

Decide between a single fish and a sorority

The two sources genuinely differ on groups. OATA treats female groups as normal; Seriously Fish warns that ornamental strains are more aggressive than other betta species and that usually only one can be kept in a tank. A group can work in a large, heavily planted aquarium, but watch closely for chasing and torn fins in the first weeks and be ready to separate a bully. Turn your measurements into litres with our tank volume calculator.

Plant densely and keep the lid on

Recreate a shaded, slow, overgrown water. Seriously Fish suggests a heavily planted aquarium with floating plants such as Salvinia or Riccia to dim the surface, rooted plants such as Cryptocoryne, and shelters such as clay pots or short lengths of pipe. Bettas are excellent jumpers, so the tank must be well covered, but they also need to gulp air.

Lay out the tank in layers

OATA asks for a gap between the water surface and any cover glass so bettas can reach air, and warns against sharp or rough décor that could tear fins. Do not fill the aquarium to the brim, as Seriously Fish advises. Fit overhead lighting for a regular day and night, which live plants also need, and keep the aquarium out of direct sunlight, draughts and noisy, vibrating spots.

Keep the water warm and stable

Bettas need a heater all year in a UK home. The three main sources give different ranges, so aim for the overlap:

Separate habitat values from waste readings

Ornamental bettas are bred for the aquarium, and Seriously Fish gives pH 6.0–8.0 for the species, adding that wild-caught fish are likely to prefer softer, more acidic water of pH 5.0–7.0. Most treated UK tap water falls inside the ornamental range. Use a thermostatic heater and check it with a thermometer; see our betta temperature guide for more on keeping bettas warm. Test your tap water and enter it in our water matcher to see how it compares.

Filter gently and change water weekly

OATA says a filter is always essential, set to give a gentle current so bettas can swim freely. Seriously Fish recommends an air-powered sponge filter and warns against strong water movement, which tires short-finned and long-finned bettas alike. Mature the filter before she arrives; our article on the nitrogen cycle explains how.

Follow a weekly maintenance sequence

1. Test ammonia, nitrite, nitrate and pH, and check the thermometer.
2. Change at least 25% of the water, as OATA advises, siphoning waste from the substrate as you go.
3. Add tap water conditioner to the new water and match its temperature to the aquarium.
4. Squeeze the sponge filter in removed aquarium water when flow drops, never under the tap.
5. Trim floating plants so open water remains at the surface.

Feed small, meaty meals

In the wild, bettas hunt small aquatic and land insects and other invertebrates. Seriously Fish says captive fish usually take dried foods once they recognise them but should also get small live or frozen foods, such as daphnia, brine shrimp and bloodworm, regularly. OATA recommends a good flake or pellet, ideally one made for bettas, fed once a day in an amount eaten within a few minutes. Seriously Fish warns that bettas are prone to obesity, so resist the temptation to feed more.

Build one measured meal

• Staple: a few Tropical Soft Line Betta granules, which sink slowly, or a pinch of Tropical Betta Flakes.
• Frozen treat: a little thawed Frozen Artemia two or three times a week.
• Occasional extra: one or two freeze-dried bloodworms, soaked first.
• Rest: many keepers skip feeding one day a week to keep bettas trim.

Kwon and colleagues linked red colour in bettas to genes involved in handling carotenoids, the pigments fish obtain from their food, so a varied diet supports the red and orange in her pattern.

Introduce her calmly

OATA describes the floating-bag method: switch off the aquarium lights, float the sealed bag for about 10 minutes so the temperatures match, add small amounts of aquarium water to the bag over up to 20 minutes, then net her out or pour her in with as little bag water as possible. Our guide to acclimatising new fish shows each step. If you are adding her to a group of females, rearranging the plants first breaks up existing territories.

Use a first-week checkpoint plan

Choose calm tank mates

Females are calmer than males, and OATA says they can join community aquariums as long as there are no boisterous or aggressive fish. Seriously Fish is more cautious: it does not recommend bettas for a standard community tank but says some small cyprinids and loaches from similar habitats may suit, after research. Two males must never share a tank, and OATA advises that a male should only be kept with five or more females in a densely planted aquarium by experienced keepers.

Screen each companion

Popular choices are a shoal of harlequin rasboras, such as our 6 × Harlequin Rasboras, and the slender, secretive Kuhli Loach. For a group of females, the 5 × Female Bettas pack or the Female Plakat Betta Mix are starting points. Read our betta tank mates guide and check any mix with the tank mates tool.

Watch for problems early

OATA describes a healthy fish as having clear, bright eyes, undamaged fins, intact scales, no ulcers or bumps, normal swimming and steady breathing. Clamped fins, flicking against décor and shimmying are warning signs. Learn her normal routine in the first few days.

Pair each sign with an action

For more on everyday care and on the many fin and colour forms, see our betta fish care guide and our guide to betta types.

Understand breeding before you pair her

OATA notes that females ready to spawn show vertical bars on the body. The male builds a bubble nest at the surface, sometimes using plant debris, and the pair spawn in an embrace beneath it; Seriously Fish describes the female catching the eggs between her pelvic fins and body before the male carries them up. OATA advises removing the female afterwards, because the male guards the nest fiercely, and turning the filter flow down.

The eggs hatch in about one day according to OATA, or 24–48 hours according to Seriously Fish, and the fry stay in the nest for three to four days. They need the tiniest foods at first, then microworm and newly hatched brine shrimp, and Seriously Fish recommends the tightest possible lid so the young breathe warm, humid air while their labyrinth organ develops. Breeding needs a separate aquarium and plenty of space to grow on the young.

Answer Candy Koi Female Betta buying questions

What is a candy koi female plakat betta?

A female Siamese fighting fish, Betta splendens, of the short-finned plakat type, with a koi pattern: a pale body splashed with red, orange, white and black, plus metallic blue scales. "Koi" and "candy" are trade names for the pattern, not separate species.

How big does a female betta grow?

About 6–7 cm. OATA gives about 7 cm, Seriously Fish 70 mm standard length and FishBase 6.5 cm total length for the species.

Can I keep one female betta on her own?

Yes. Seriously Fish says ornamental bettas are usually best kept one per aquarium, and a single female is the simplest choice. Plan for a base of at least 45 × 30 cm, about 41 litres, which Seriously Fish recommends for a single betta.

Can female bettas live together?

Sources differ. OATA says females are calmer than males and can be kept in groups of at least four in 60 litres or more, while Seriously Fish warns that ornamental strains are more aggressive than other bettas and usually only one can be kept per tank. If you try a group, plant it densely and have a spare aquarium ready.

What temperature does she need?

A heated tropical aquarium. OATA gives 20–28°C, Seriously Fish 22–30°C and FishBase 24–30°C, so 24–28°C suits every source.

What should I feed her?

Betta pellets or granules once a day, only as much as she eats in a few minutes, with small frozen or live foods such as daphnia, brine shrimp and bloodworm as treats. Bettas put on weight easily, so do not overfeed.

Will her colours change?

They may. Breeders widely report that koi and other marble-type bettas keep changing pattern as they mature, although we have not found a scientific study of the genes involved. Colour also brightens as a fish settles and dulls when it is stressed.

Can she live with other fish?

OATA says females can join community aquariums that hold no boisterous or aggressive fish. Calm, small fish such as harlequin rasboras and kuhli loaches are typical choices. Never keep her with a male betta except briefly for supervised breeding.

What exactly will I receive?

One live female candy koi plakat betta of medium-large size. The photographs show the colour form; every koi betta has its own pattern, so yours will differ.

Consult the care references

• Seriously Fish: Betta splendens — native range, habitat, adult size, aquarium size, water values, set-up, diet, behaviour, sexing and breeding.
• OATA: How to look after bettas (Siamese fighting fish) — UK trade guidance on betta aquarium size, keeping females, water values, feeding, introduction, health and breeding.
• FishBase: Betta splendens — maximum length, water values, wild habitat and the species’ IUCN Red List status.
• Kwon et al. 2022, Science Advances 8: genomic consequences of domestication of the Siamese fighting fish — genomic study of betta domestication, ancestry from other Betta species and the genetics of red colour.
• Tropical Fish Co delivery policy — current dispatch days and Live Arrival Guarantee terms.