How to Care for Newborn Guppies: Top 7 Tips for Beginners (2025)

Published: 3 Apr 2025

Guppies are some of the most beloved freshwater fish for hobbyists worldwide. Their colorful appearance, playful behavior, and ease of breeding make them ideal for beginners and experts alike. But when it comes to raising their babies—called fry—many aquarium owners wonder: how to care for newborn guppies?

In this detailed guide, we’ll cover everything you need to know, from preparing your tank before birth to raising strong, healthy guppies. Whether you’re setting up your first fry tank or want to boost your fry survival rate, this guppy fry care guide will help you every step of the way.

Table of Content

Understanding Guppy Reproduction

Before you raise guppy fry, it’s good to understand how guppies reproduce.

1. Mating Behavior and Fertilization

Guppies are livebearers, which means the female gives birth to live young instead of laying eggs. Males have a modified fin called a gonopodium used for mating. Fertilization occurs inside the female.

2. Gestation and Signs of Pregnancy

Pregnancy in guppies lasts about 21–30 days. Signs of pregnancy include:

A dark gravid spot near the back of the abdomen
A square-looking belly
Hiding behavior and slower movement

3. The Birth Process

Once labor begins, the female may give birth to 20 to 100 fry over several hours. Immediately after birth, adult guppies may try to eat the fry, which is why separation is crucial.

Preparing for the Arrival of Fry

Getting your tank ready before the fry is born is one of the most essential guppy fry care tips.

1. Set Up a Breeding Tank or Breeder Box

Move the pregnant female to a separate tank or breeder box to protect the fry. This prevents adult fish from eating the fry after birth.

2. Ideal Water Conditions

Maintain these parameters:

Temperature: 78°F to 80°F (25.5°C – 26.5°C)
pH: 7.0–7.8
Water Hardness: Moderate (8–12 dGH)

Stable conditions help the fry survive their first few critical days.

3. Add Hiding Spots

Live or silk plants, such as Java moss or floating plants, can be used to offer cover. Fry naturally hide, reducing their chances of being eaten.

Immediate Post-Birth Care

Once the fry is born, it’s time for quick action.

1. Separate Fry from Adults

If you used a breeder box, remove the female soon after birth. If using a tank, transfer the fry to a separate nursery tank.

2. Monitor Their Health

Look for signs of healthy fry:

Active swimming
Clear, bright eyes
Full, rounded bellies after feeding

Any weak or motionless fry should be separated to avoid disease spread.

Feeding Newborn Guppies

One of the most common questions is: What should be fed to guppy fry?

Best First Foods
Infusoria (homemade or store-bought) Baby brine shrimp (live or frozen) Crushed flake food (powder-fine) Commercial liquid or powdered fry food

These tiny foods fit the fry’s small mouths.

2. Feeding Schedule

Feed small amounts 3–5 times a day. Uneaten food should be removed quickly to avoid fouling the water.

3. Transitioning to Bigger Foods

At around 3–4 weeks, the fry can start eating:

Micro worms
Crushed pellets
Finely chopped bloodworms or daphnia

This stage is vital for their guppy fry growth stages.

Maintaining Optimal Water Quality

Healthy water is the foundation of good guppy fish fry care.

1. Regular Water Changes

Change 20–30% of the water every 2–3 days. Always use dechlorinated water at the same temperature as the tank.

2. Filtration for Fry Tanks

Use sponge filters—they’re gentle and won’t suck up fry. Keep flow low to avoid stressing the tiny fish.

3. Monitor Water Parameters

Use test kits to track:

Ammonia (should be zero ppm)
Nitrites (0 ppm)
Nitrates (<20 ppm)

Stable readings = healthy fry.

Promoting Healthy Growth and Development

1. Ensure Enough Space

Fry needs room to grow. Avoid overcrowding by moving them to larger tanks as they grow.

2. Proper Lighting

Use a regular aquarium light on a 10–12 hour cycle. Good lighting helps with feeding and plant growth.

3. Preventing Disease

Watch for signs like:

Clamped fins
White spots (ich)
Lethargy

Isolate and treat sick fry quickly with approved medications or salt baths.

Tracking Growth: Guppy Fry Development Stages

Knowing the guppy fry growth chart helps you track progress:

Age	Size
1 Week	0.2 – 0.4 cm
2–3 Weeks	0.5 – 0.7 cm
4–5 Weeks	0.8 – 1.0 cm
6–8 Weeks	1.2 – 1.5 cm
8+ Weeks	2+ cm

Identifying Male vs. Female Fry

You can usually identify the gender at 4–6 weeks:

The male fry develop bright colors and a gonopodium
The female fry grow more extensive and rounder, with a gravid spot

Understanding this helps with future breeding and tank management.

How to Raise Guppies in a Tank: Long-Term Tips

how to raise guppies in a tank

Keep tanks covered to prevent jumping
Feed a varied diet (flakes, veggies, protein)
Maintain regular tank maintenance and cleaning
Avoid sudden temperature or pH swings
Keep compatible tankmates (no fin-nippers)

Following these steps ensures a healthy life for everyone, from fry to adult guppies.

How to Safely Integrate Guppy Fry into the Main Tank Without Risk

Integrating guppy fry into the main aquarium should be done carefully to avoid stress, injuries, or predation. Follow these key steps for a safe and smooth transition:

Wait until the fry is ready:
Fry should be at least 6–8 weeks old and around 1 inch in size. At this stage, they’re less likely to be eaten by adult fish.
Match water parameters:
Ensure temperature, pH, and hardness are consistent between the fry tank and the main aquarium.
Use slow acclimation:
Try the drip acclimation method or float their container for 20–30 minutes to avoid shock.
Provide plenty of hiding spots:
Add live or artificial plants, rocks, and decorations to give fry safe places to retreat.
Observe adult fish behavior:
Watch closely for nipping, chasing, or bullying from older fish. Remove aggressive fish if necessary.
Feed carefully:
Offer food near hiding areas so fry can eat without competing with larger tank mates.

Your fry can join the main tank and grow into healthy adult guppies with patience and proper care.

Conclusion

Caring for guppy fry is a rewarding experience. From birth to adulthood, each stage offers new insights and challenges. By following this guide, you’ll know how to care for newborn guppies safely, healthily, and successfully.

Whether breeding for fun or building a colony, always aim for clean water, proper feeding, and safe environments. These small steps create a significant impact.

Have you raised guppy fry before? What worked best for you? Share your tips in the comments below!

FAQ: How to Care for Newborn Guppies

Can guppy fry survive in a community tank with adult fish?

While it’s possible, raising guppy fry in a community tank is not recommended unless it’s heavily planted with hiding spaces. Most adult fish, including adult guppies, see newborn fry as food and may eat them. If you must keep them in the same tank, use floating plants, breeding boxes, or dense vegetation like Java moss to improve survival rates. However, always separate them into a nursery tank for the highest fry survival.

Do guppy fry need an air pump or bubbler in their tank?

Yes, guppy fry benefits from having an air pump or gentle sponge filter to maintain oxygen levels in the water. Good oxygenation helps with fry metabolism, digestion, and growth. Avoid powerful filters or bubblers that create strong currents, which may stress or exhaust the fry. Sponge filters are ideal because they provide both biological filtration and aeration without sucking in tiny fry.

Is it necessary to use a heater for a guppy fry tank?

Absolutely. Guppy fry are tropical fish and need a stable water temperature between 78°F and 80°F (25.5°C —26.5°C). A small aquarium heater helps prevent temperature fluctuations, which can stress the fry and slow their growth. Cold water conditions may also suppress their immune system and lead to higher mortality rates. A digital thermometer can help you monitor the temperature accurately.

Do guppy fry need light at night to grow properly?

No, guppy fry does not need light at night. Just like adult fish, they benefit from a natural light-dark cycle. Keep your aquarium light on for 10–12 hours during the day and turn it off at night to mimic a natural day/night rhythm. Continuous light can lead to stress and disrupt sleep cycles, which may impact fry development. Use a timer if needed for consistency.

Can I keep guppy fry with shrimp or snails?

Yes, peaceful invertebrates like cherry shrimp, Amano shrimp, or nerite snails are generally safe tankmates for guppy fry. They won’t hurt the fry and can help maintain water quality by eating leftover food and algae. However, constantly monitor interactions to ensure your fry is not harassed, especially in smaller tanks. Snails and shrimp can be a good choice if you’re looking for companions that won’t threaten fry survival.