Breeding Guppies — A Beginner's Guide

Learn how to breed guppies! Setup, selective breeding, raising fry, and avoiding common mistakes.

zucht · 8 Min. Lesezeit · breeding, guppies, livebearers, fry

Breeding Guppies — A Beginner's Guide

Guppies (Poecilia reticulata) are livebearers that breed prolifically. Here's how to breed them intentionally and raise healthy fry.

Why Breed Guppies?

Pros:

Excellent beginner breeding project
Livebearers (no egg care needed)
Prolific (30-60 fry per batch!)
Can selectively breed for colors/patterns
Profitable hobby (sell to LFS or hobbyists)

Cons:

Can overpopulate tanks quickly
Need space for grow-out tanks
Selective breeding requires culling

Guppy Breeding Basics

Sexual Dimorphism (Identifying Males vs Females)

Males:

Smaller body (2-3cm)
Bright, colorful fins and tail
Gonopodium (modified anal fin = breeding organ)
Slender body

Females:

Larger body (4-6cm)
Dull colors (gray, tan, sometimes colorful)
Rounded anal fin
Gravid spot (dark spot near vent when pregnant)

Ratio: Keep 2-3 females per male (reduces harassment)

How Guppies Reproduce

Guppies are livebearers:

Male uses gonopodium to fertilize female internally
Gestation: 21-30 days (temperature-dependent)
Female gives birth to live, free-swimming fry (not eggs!)
Fry are immediately independent (but vulnerable to predators)

Superfetation: Females can store sperm for months — one mating = multiple batches of fry!

Setting Up for Breeding

Option 1: Community Breeding (Easiest)

Just let them breed in the main tank!

Pros:

No extra equipment
Natural selection (strong fry survive)

Cons:

Adult fish eat most fry
Few survivors (5-10% survival rate)

Best for: Casual breeding, maintaining population

Option 2: Breeder Box (Low-Effort)

Plastic/mesh box that floats or hangs inside tank.

How it works:

Move pregnant female to breeder box
She gives birth inside
Fry fall through slits (too small for mother to reach)
Remove mother after birth

Pros:

Cheap (€5-15)
Protects fry from adults

Cons:

Stressful for mother (confined space)
Limited fry space (overcrowding)

Best for: Small-scale breeding, occasional batches

Option 3: Dedicated Breeding Tank (Best Results)

Separate 40-80L tank for breeding.

Setup:

Sponge filter (gentle, won't suck up fry)
Heater (26-28°C = faster growth)
Floating plants (Guppy grass, Water Sprite) for fry hiding
No substrate (easier to clean, siphon uneaten food)

Process:

Place gravid female in breeding tank
She gives birth (usually at night or morning)
Remove mother after birth
Raise fry to 1-2cm, then move to grow-out tank

Pros:

Highest survival rate (90%+)
Control breeding pairs
Observe fry growth closely

Cons:

Requires extra tank
More maintenance

Best for: Serious breeders, selective breeding programs

Selective Breeding (Improving Your Strain)

Want specific colors/patterns? Breed selectively!

Steps:

Choose breeding pair:
Select male with desired traits (color, fin shape)
Select large, healthy female

Isolate pair in breeding tank

Raise fry and cull weak/deformed/unwanted colors

Select best offspring for next generation

Repeat for 3-5 generations to stabilize traits

Popular guppy strains:

Red Mosaic
Blue Moscow
Cobra (snakeskin pattern)
Tuxedo
Leopard
Half-Black (HBPB, HBRT)

Tip: Keep detailed records (lineage, traits, dates) to track genetics.

Caring for Pregnant Females

Signs of Pregnancy:

Gravid spot darkens (dark area near vent)
Belly becomes square-shaped (not just round)
Behavioral changes (hiding, restless swimming)

Gestation: 21-30 days (shorter in warmer water)

Just before birth:

Female isolates herself
Gravid spot very dark
"Boxy" belly shape
May refuse food

Don't stress her! Avoid netting or moving late-stage pregnant females unless necessary.

Raising Guppy Fry

First 24 Hours:

Don't feed immediately (fry live off yolk sac for 12-24 hours)
Provide hiding spots (plants, moss)
Keep water clean (siphon uneaten food daily)

Feeding Schedule:

Week 1-2:

Feed 3-5× daily (small amounts)
Foods: Baby brine shrimp, finely crushed flakes, micro worms

Week 3-4:

Feed 3× daily
Foods: Brine shrimp, crushed flakes, Hikari First Bites

Week 5+:

Feed 2× daily
Foods: Small flakes, micro pellets, frozen foods

Tip: Live baby brine shrimp is the BEST food for fast growth and vibrant colors!

Water Changes:

Daily 10% water changes for first 2 weeks (removes waste, stimulates growth)
Then 25% every 2-3 days

Match temperature! Sudden temp drops shock fry.

Growth Timeline:

Week 1: 3-5mm (tiny!)
Week 4: 1cm (starting to show color)
Week 8-12: 2-3cm (sexing possible)
Week 12-16: Adult size (ready to breed or sell)

Males color up faster than females.

Culling (Selective Removal)

Not all fry should be kept.

Cull fry with:

Deformities (bent spine, missing fins)
Extremely weak (can't swim, starving)
Unwanted colors (if breeding for specific strain)

Humane culling method:

Clove oil (see fish disease guide)
Donate to LFS as feeder fish (if allowed)

Don't release into wild! Guppies are invasive.

Selling or Rehoming Guppies

Once you're breeding, you'll have LOTS of guppies!

Options:

Sell to local fish store (€0.50-1 per guppy, less for bulk)
Sell online (local classifieds, forums)
Give to friends/club members
Trade for other fish/equipment

High-quality strains (Moscow, show guppies) can sell for €5-15+ each!

Common Breeding Problems

1. Fry Eaten by Adults

Solution: Remove adults or use breeder box/separate tank.

2. Low Survival Rate

Causes: Poor water quality, overfeeding (pollutes water), starvation

Solution: Frequent water changes, feed small amounts 3-5× daily

3. Deformed Fry

Causes: Inbreeding (brother-sister mating), poor genetics

Solution: Introduce new bloodlines every 3-4 generations, cull deformed fry

4. Female Won't Give Birth

Causes: Stress, not actually pregnant, complications

Solution: Provide hiding spots, ensure water quality, wait (false pregnancy happens!)

5. Inbreeding Depression

Symptoms: Smaller size, weaker fish, deformities, lower fertility

Solution: Outcross every 3-4 generations (introduce unrelated guppy to refresh genetics)

Conclusion

Guppy breeding is fun, rewarding, and educational!

Start simple:

Let them breed naturally in community tank
Rescue a few fry to practice raising
Upgrade to breeding tank once hooked

Selective breeding for colors:

Choose specific strain (Red Moscow, Blue Cobra, etc.)
Breed best to best each generation
Cull ruthlessly (only keep top 20-30%)
Document lineage to avoid inbreeding

Guppies are the perfect breeding project — easy, fast, and beautiful!

Warning: Once you start, you'll want 5+ tanks. It's addictive!

Breeding Guppies — A Beginner's Guide