Raising betta fry is the most delicate — and most important — phase of breeding Betta splendens. The first 30 days determine survival rate, growth speed, fin development, and ultimately the quality and value of your juvenile bettas.

Many breeders succeed at spawning but lose large numbers of fry due to feeding errors, poor water control, or improper grow-out systems. This complete survival guide walks you through:

Exact feeding schedules (day-by-day)
Water change strategies that prevent shock
Equipment setup for fry tanks
Growth milestones
Separation timing
Cost considerations
Mistakes that wipe out entire batches

If your goal is healthy juveniles with strong coloration, symmetrical fins, and high survival percentages, this guide covers everything step by step.

Why the First 30 Days Matter Most

Betta fry are:

Extremely small at hatch
Weak swimmers
Sensitive to ammonia
Dependent on microscopic food
Vulnerable to temperature swings

The difference between 20% survival and 80% survival almost always comes down to:

Proper early feeding
Gentle filtration
Stable temperature
Gradual water increases

When raised correctly, a single spawn can produce 50–200 strong juveniles ready for sale or grow-out.

Overview: Betta Fry Development Timeline (0–30 Days)

Day	Stage	Key Focus
Day 0	Eggs hatch	No feeding
Day 1–3	Wigglers (attached to nest)	Male guards
Day 3–5	Free swimming	Start micro foods
Day 5–10	Rapid early growth	Increase feeding frequency
Day 10–20	Visible size increase	Introduce baby brine shrimp
Day 20–30	Fin development begins	Larger water changes

Understanding this timeline prevents common feeding and filtration mistakes.

Tank Setup for Raising Betta Fry

If you used a breeding tank, you may continue using it for the first 2–3 weeks.

Ideal Fry Tank Specifications

5–10 gallons
Bare bottom
Sponge filter (very gentle flow)
Heater set to 80°F (26–27°C)
Water depth: 4–6 inches initially

Never use strong filters — suction kills fry instantly.

Day 0–3: Hatching & Wiggler Stage

After spawning:

Eggs hatch in 24–48 hours.
Fry hang vertically from the bubble nest.
The male retrieves falling fry.

Important:

Do NOT feed yet.

They absorb nutrients from their yolk sacs.

Remove the male once fry are free-swimming (usually day 3–5).

Failure to remove him can result in fry being eaten.

Day 3–7: First Feeding Stage (Critical Window)

This stage determines survival rates.

Betta fry are too small for regular fish food.

Best First Foods

Infusoria
Vinegar eels
Commercial liquid fry food

Feed tiny amounts 3–5 times per day.

Why So Often?

Fry have tiny stomachs and need constant access to micro-sized food.

Overfeeding causes ammonia spikes — the leading cause of early die-offs.

Day 7–14: Transition to Baby Brine Shrimp

This is the growth acceleration phase.

Ideal Food: Baby Brine Shrimp (BBS)

Why BBS?

High protein
Stimulates rapid growth
Improves survival rate
Encourages strong fin development

Feed 2–4 times daily in small portions.

You’ll notice:

Orange bellies after feeding
Faster swimming
Noticeable size difference in days

Microworms can also supplement feeding.

Day 14–21: Controlled Growth Phase

By week two:

Fry size doubles or triples
Some aggression may begin
Water quality becomes more critical

Increase Water Volume Gradually

Add small amounts of aged, heated water daily.

Gradual increases:

Improve growth
Dilute waste
Reduce stress

Do NOT suddenly fill the tank.

Day 21–30: Early Juvenile Stage

Now the real growth begins.

You’ll start seeing:

Fin ray development
Early coloration
Dominance behavior

Continue feeding:

Baby brine shrimp
Finely crushed high-protein pellets
Frozen daphnia (optional)

Feed 3 times daily.

Feeding Schedule Summary (First 30 Days)

Age	Food Type	Frequency
Day 0–3	None	0
Day 3–7	Infusoria / Liquid food	3–5x daily
Day 7–14	Baby brine shrimp	2–4x daily
Day 14–30	BBS + crushed pellets	3x daily

Consistency is more important than quantity.

Water Change Strategy for Maximum Survival

Poor water management kills more fry than disease.

Week 1

10% daily (drip method)

Week 2

15–20% daily

Week 3–4

20–30% daily

Always:

Match temperature
Use dechlorinated water
Add water slowly

Turkey basters are ideal for removing debris without harming fry.

Growth Benchmarks by Day 30

By one month:

Size: 0.5–0.75 inches
Active swimming
Clear fin separation
Early signs of sex differentiation

If fry are undersized, review:

Feeding frequency
Protein intake
Water change consistency

When to Separate Males

Around 4–6 weeks:

Flaring begins
Nipping observed
Aggression increases

Separate males into individual containers to prevent injury.

Females can remain grouped longer.

Equipment Checklist for Raising Betta Fry

✔ 5–10 gallon tank

✔ Adjustable heater

✔ Sponge filter

✔ Air pump

✔ Thermometer

✔ Turkey baster

✔ Brine shrimp hatchery kit

✔ Fry-safe food cultures

Cost Breakdown for Fry Rearing Setup

Item	Estimated Cost
Fry tank	$25–$50
Heater	$20–$30
Sponge filter	$10–$15
Air pump	$15–$25
Brine shrimp kit	$20–$40
Fry food supplies	$20–$40

Total estimated setup: $110–$200

High survival rates can offset this quickly if juveniles are sold.

Comparison Table: Proper Fry Care vs Poor Fry Care

Factor	Proper Care	Poor Care
Survival Rate	70–85%	20–40%
Growth Speed	Fast	Stunted
Fin Quality	Strong	Deformed
Water Clarity	Stable	Cloudy
Aggression Control	Managed	Chaotic

Correct feeding + stable water = predictable results.

Common Mistakes That Kill Betta Fry

Overfeeding
No daily water changes
Strong filter flow
Temperature fluctuations
Not culturing live food ahead of time
Delayed male removal
Sudden water volume increase

Avoid these and survival rates improve dramatically.

Advanced Tips for Higher Survival Rates

Maintain 80°F Consistently

Lower temperatures slow metabolism and growth.

Feed Small, Frequent Meals

Better than large feedings.

Cull Deformed Fry Early

Improves overall tank health.

Upgrade to Grow-Out Tank at 4 Weeks

A 20-gallon tank improves long-term development.

Monetization & Value Considerations

Healthy, well-raised juveniles:

Develop brighter coloration
Show stronger finnage
Command higher resale prices

Common juveniles may sell for $5–$15.

Premium strains can reach $30–$80+ per fish.

High survival rates dramatically improve returns from each spawn.

Frequently Asked Questions

How many betta fry survive normally?

Without proper care: 20–40%.

With structured care: 70–85% or higher.

Can I raise betta fry without live food?

Survival rates drop significantly without live micro foods.

When do betta fry show color?

Usually between weeks 3–6.

How long before fry are sellable?

Typically 8–12 weeks.

Final Thoughts

Raising Betta splendens fry successfully is a daily commitment during the first 30 days. The difference between success and mass loss comes down to:

Proper feeding transitions
Stable temperature
Gentle filtration
Consistent water changes
Timely separation

Control these variables and your results become consistent and predictable.

The first 30 days are intensive — but they determine everything that follows.

Thanks for reading How to Raise Betta Fry: Survival Guide for the First 30 Days

How to Raise Betta Fry: Survival Guide for the First 30 Days