Breeding bettas is one of the most rewarding — and one of the more challenging — projects a home aquarist can take on. Not because bettas are hard to spawn (they’re actually easier than most fish), but because raising the fry is intensive, time-consuming, and produces 100+ juvenile fish that all need eventual homes.

This guide covers the honest process. From pair selection through first spawn to raising fry to sale size, with the specific UK context.

Before you start

Realistic timelines:

• Pair conditioning: 2 weeks
• Spawning setup: 1 day
• Spawn itself: 4–6 hours
• Egg to hatch: 36–48 hours
• Fry raising to sale size: 8–12 weeks

Realistic effort:

• Daily 20–50% water changes for the fry-raising tank
• Baby brine shrimp hatching daily
• 100+ juvenile bettas to sex, separate, and eventually rehome
• Total effort ~1 hour per day for the fry-raising period

Realistic economics:

• Basic dumbo/veiltail betta fry sell for modest sums at UK aquatic shops
• Fancy morphs (koi galaxy, dragon scale, doubletail) fetch considerably more to hobbyists
• Total revenue per successful spawn is modest but worthwhile, realistically

Not a get-rich-quick project. A dedicated hobby.

Selecting the breeding pair

Male

• Adult male, 6+ months old
• Vibrant colouration
• No fin damage or disease
• Aggressive display when shown to another male
• Buy from a reputable UK breeder, not big-box pet shops — see our betta care guide for buying advice.

Female

• Adult female, 6+ months old
• Slightly plump body (indicates egg development)
• Willing to display “breeding bars” (vertical stripes) when male shown
• Compatible with male’s colour/pattern strain
• From same breeder if possible for genetic compatibility

Compatibility: most bettas breed with any female of their species. Specific colour breeding is a separate skill (see below).

The breeding tank

Separate tank required. Do NOT breed bettas in a community tank — eggs and fry are eaten immediately.

Setup:

• Tank size: 20–40L. Bigger is easier but harder to control.
• Water level: LOW — 15–20 cm deep only. Bettas build bubble nests near surface; fry need shallow water to reach surface for air.
• Bare bottom OR fine substrate — bare bottom easier for cleaning.
• Sponge filter with air pump — gentle flow. See our best aquarium filter UK guide.
• Heater — set to 27–28°C. See our best aquarium heater UK guide.
• Dense floating plants — Amazon frogbit is ideal. Male builds bubble nest under floating plants.
• Alternative bubble nest substrate: Indian almond leaf or a piece of Styrofoam.
• Cover for female — ceramic caves or plants. She needs somewhere to escape male aggression.
• Tight lid — fry need warm humid air above water for labyrinth organ development.

Water chemistry:

• pH 6.5–7.0
• Temperature 27–28°C
• Softer water preferred — Indian almond leaves help.
• Cycled first — see our UK cycling guide.

Conditioning the pair (2 weeks)

Both fish fed heavily on live/frozen food to trigger reproductive readiness.

Daily feeding:

• Frozen bloodworm — 2× daily
• Frozen brine shrimp — 2× daily
• Live daphnia or blackworms if available
• Hikari Betta Bio-Gold pellets for variety

Signs conditioning is working:

• Male: brighter colours, actively displaying, building small trial bubble nests
• Female: plumper belly, visible “breeding bars” (vertical stripes)
• Both: increased activity, appetite

Introducing the pair

Do NOT put them in the same tank immediately. Betta aggression is unpredictable; without prior introduction, one may kill the other.

Correct introduction:

1. Add female to breeding tank in a plastic breeder box (transparent container inside the tank). She can see and be seen but is protected.
2. Add male to the main tank. He’ll investigate, display, possibly build a bubble nest.
3. Wait 24–48 hours. Observe behaviour.

• Female shows breeding bars (vertical stripes) = she’s receptive
• Male builds a large bubble nest = he’s ready
• Female consistently hides / males aggressive display without pause = wait longer or try a different pair

1. When both show readiness signs, release the female into the main tank.

Watch continuously for first 30 minutes. If aggression is severe (torn fins, extended attacks), remove female — pair not compatible.

The spawning event

1. Male chases the female with quick “dart” motions
2. Female approaches the bubble nest
3. Male “wraps” around female (embrace)
4. Female releases eggs; male fertilises and catches them as they sink
5. Male retrieves eggs in his mouth, spits them into the bubble nest
6. Repeated over 3–5 hours — spawning is not one event but many
7. Total eggs: 50–500 per spawn

Post-spawn: remove the female IMMEDIATELY

Once spawning stops:

• Remove the female — male becomes aggressive and will kill her
• Female goes to a recovery tank with clean warm water and gentle feeding
• Male stays with the eggs — he tends the nest for the next 24–48 hours

Egg to hatch (36–48 hours)

• Male catches falling eggs and returns them to the nest
• Eggs turn cloudy grey → then eyes visible → then tail visible
• Fry hatch and briefly dangle from the nest
• Free-swimming fry appear after 3–4 days from spawning

Once fry are free-swimming: remove the male

• Male may start eating fry once they’re free-swimming
• Move male to a recovery tank for 2 weeks

Raising the fry (the hard part)

First feeding (day 5–7 post-spawn):

• Infusoria (microscopic single-celled organisms) — cultured in advance, added to tank
• Baby brine shrimp after day 10 — freshly hatched, ideal size and nutrition
• Powdered fry food (Hikari First Bites) as supplement

Feed 5–8 times daily, small amounts. Fry graze constantly.

Daily maintenance:

• 50% water change with matched-parameter water
• Vacuum bottom — accumulated waste
• Check fry activity — active swimming = healthy

Weeks 3–6:

• Fry double weekly
• Transition to crushed flake, small pellets
• Grow-out tank with sponge filter and gentle flow
• Reduce daily water changes to 30%

Weeks 6–12:

• Fry reach 2–3 cm
• Sexes become distinguishable
• Colour patterns develop
• Separate aggressive males into individual jars/cups (adult betta housing)
• Females may stay in a sorority group until 3+ months old

Sexing juveniles

By 8 weeks:

• Males: more elaborate finnage, brighter colours, sometimes visible egg tube behavior
• Females: rounder body, shorter fins, distinctive white egg tube behind ventral fin

By 12 weeks, sexing is reliable.

What to do with the fry

Options:

• UK aquatic shops — most accept healthy betta fry. Basic veiltails fetch modest store credit; fancy morphs fetch considerably more.
• UK betta breeders / hobbyists — trade with other breeders; higher prices for fancy strains.
• UK betta breeder groups on Facebook — active community.
• Big-box pet chains — accept but at lower prices.

Never release into UK waterways — illegal, ecologically damaging.

Colour breeding

Selecting for specific colours over multiple generations:

• Line breeding: breeding parents to offspring for consistent traits
• Line splitting: separating lines to develop distinct colours
• Test crossing: breeding two parents to see offspring quality

Popular UK strains: koi galaxy, dumbo, half-moon, plakat, giants, mustard gas.

Serious breeding requires:

• Multiple pairs (10+)
• Detailed genetic tracking
• Multi-year timelines
• Willingness to cull weak fry

Common problems

Fry die within 48 hours — usually failed hatching or ammonia spike. Test water; check heater.

Male eats eggs — inexperienced first-time breeders often do. Try again next spawn.

Female severely injured during spawning — pair not compatible. Try different pairing.

Fry not swimming after hatching — insufficient temperature or oxygen. Verify 27°C, add gentle aeration.

No pair bonding after 48 hours — try different fish; some individuals never breed.

Bottom line

Betta breeding rewards patience and preparation. An inexpensive pair of good stock, some tanks and equipment, and 8 weeks of dedicated fry-raising produces 30–80 sellable juvenile bettas. Time investment: ~1 hour/day during fry-raising period.

Not a project for casual aquarists. But for hobbyists genuinely engaged with the fish and interested in genetics + husbandry, one of the most rewarding fish-breeding projects available in the UK.

Frequently asked questions

How do you breed betta fish?

Condition a pair on live food, place the female in the breeding tank behind a divider, and release her when both show readiness. After spawning, the male tends the bubble nest — remove the female immediately.

How long does it take to breed bettas?

Conditioning takes about two weeks, spawning a few hours, and eggs hatch in 36–48 hours. Raising fry to sale size then takes 8–12 weeks of daily care.

How many fry do bettas have?

A single spawn produces 50–500 eggs, though far fewer survive to adulthood without intensive fry care including live food and daily water changes.

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Related: betta fish care, breeding livebearers, breeding corydoras, breeding guppies, cherry shrimp breeding.

— Jaqline Smalling, FishForever