betta fry growth

Betta Fry Growth: Power-Growing Fry

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Most keen betta owners decide to try to breed from their male betta at some point. If you provide your bettas with the right tank conditions, nature will usually take its course, and your fish will breed naturally.

In this article, we’re going to take a closer look at a common problem that’s experienced by most betta hobbyists – how to improve your baby bettas’ growth rate.

Why breed bettas?

Betta fish come in such a range of types and colors that it can be fascinating to breed them just to see what you can create. 

Amateur hobbyists might be happy to wait many months to see the results of their efforts and careful nurturing, but it can be frustrating to learn that some professional betta breeders are apparently able to produce fully-developed, beauties after just two or three months. 

So, what’s the advantage of growing bettas so quickly? 

Well, the main gain is that you can achieve your breeding goals much faster, as you can perform another filial spawning every three or four months, rather than only every seven to eight months. That means that you can move onto subsequent generations of fish as quickly as possible, which allows you to create even more color combinations.

How to power-grow betta fry

If you enjoy showing your bettas, or you want to sell them to other enthusiasts, you’ll want to grow your fish as quickly as possible. Growth rates can be accelerated by providing your betta fry with the optimum conditions.

Successfully raising fry demands that you provide the proper environment for them, and you must be diligent in their maintenance and care. The growing tank must be kept pristine, and the water conditions must be right. You’ll need to feed the fry regularly and appropriately for each stage of their growth. Betta fry will only eat live food and tiny particles at that. As the fry grow, they must be moved into new containers, particularly as young males begin to grow and become more territorial.

So, when you consider that each spawning can produce between 50 and 300 fry, that’s a lot of work!

Fry Grow-Out tank

There are several different methods used by breeders for growing-out betta fry. Some breeders transfer the fry right away into a grow-out tank, whereas others keep the fry in the breeding tank for the first three to four weeks before moving them to the grow-out tank.

However, regardless of what method you prefer, you will ultimately need to move the fry to a special grow-out setup. Here’s what you’ll need for a betta fry growing tank:

  • 20+ gallon capacity tank
  • Tank cover to prevent the fry from jumping out
  • Heater
  • Filtration system
  • Lighting (natural daylight is fine, or you can use a standard aquarium light)
  • Siphon for water changes. Use a turkey baster or narrow-gauge flexible tubing, as regular gravel siphons are too powerful 
  • Live plants provide infusoria (a natural food source for young fry), so you’ll need to include some in your grow-out tank setup

Water quality

Betta fry are highly susceptible to poor tank conditions, including water quality and temperature. 

Pristine water quality is essential for successfully raising fry and stimulating fast growth.

The ideal pH for a betta fry tank is 7 to 7.2. So, you’ll need to check that daily, using a strip test kit or similar. If the pH is unstable, you’ll need to add a suitable stabilizer to the water and keep a close eye on the level by testing the water at least once every day.

The correct water temperature is a crucial element for successfully maintaining and growing the fry. The temperature in the grow-out tank should be between 850 and 880 Fahrenheit for optimal growth. Put a thermometer at the end of the tank opposite the heater. That enables you to check that the temperature is evenly distributed throughout the tank. Fry are highly sensitive to fluctuations in temperature, so you must ensure that conditions remain constant and stable.

Water Changes

To keep the water quality perfect in the grow-out tank, you’ll need to carry out water changes daily from when the fry are about two weeks old. Some breeders recommend changing 25% of the water twice each week, while others suggest changing a smaller amount of water each day.

The safest and most effective method of carrying out water changes is to use a siphon to remove water, dead fry, and uneaten food from the tank. You can’t use a regular tank siphon for this job, as, at just a few weeks old, the fry are tiny, and you risk sucking them up or killing them with a sudden rush of water.

Instead, use a length of narrow-gauge flexible tubing or a turkey baster. Airline hose is perfect for the job, and you can insert a narrow stick, such as a chopstick, into the end of the hose to slow down the flow of water even further and give you more control.

Start by vacuuming any detritus from the tank bottom up to about 50% of your total water change volume. Then, remove the remaining 50% of the water from the top of the tank, using a clear cup. That’s quicker than siphoning, and it also enables you to see if you’ve accidentally caught any of your fry.

Refill the grow-out tank with treated/aged water.


Betta fry are known to produce a Growth Inhibiting Hormone (GIH) that retards the growth of the other fry. That can mean that you’ll end up with a whole tank full of tiny fry that never seem to grow. So, as well as providing your fry with optimal water quality, frequent water changes will help to reduce the amount of GIH that may be released into the grow-out tank. To ensure that your fry’s growth is not stunted by GIH, daily water changes of 50% to 70% are recommended by many breeders.

GIH is thought to keep the fry at a size appropriate to their surroundings. So, once you have individually jarred your fry, you should carry out 100% water changes every day, which will maximize the baby betta’s growth by removing the GIH that could otherwise restrict the fish’s growth to the size of his jar.

Feeding betta fry

Very young betta fry eat nothing but live food. Once the fry are older, you can introduce pellets to their diet.

The following live foods are perfect for raising betta fry:

  • Infusoria
  • Vinegar eels
  • Micro-worms
  • Walter worms
  • Banana worms
  • Baby brine shrimp
  • Daphnia
  • Fairy shrimp
  • Grindal worms

You may be able to purchase these foods from a good fish store as a special order. Alternatively, you can buy online or cultivate your own foods using a special kit. 

It’s recommended that you obtain the cultures before you begin the breeding process. Once the bettas spawn, you’ll need to begin growing the cultures so that you have them available as soon as the betta fry are free-swimming. Note that most cultures prefer dark areas, and they can smell pretty bad, too, so you may want to keep your fry food somewhere out of the way. 

Once the fry have broken away from their egg sacs under the bubble nest and are free-swimming, you can begin to feed them. Offer the fry several small feeds every day, rather than two larger feeds. Ideally, feed your fry three to four times daily for the best results. Smaller meals will help to ensure that all the food is eaten. That’s important for the water quality in the grow-out tank, as discarded food will quickly begin to contaminate the water.

Step-by-Step Fry-Feeding Guide

Here’s a rough guide to feeding your betta fry for optimum growth and health:

  1. Start by feeding the fry with nematodes. At this time, the fry will also be feeding on infusoria that they will get from the leaves of live plants in the tank.
  2. When the fry are a few days old, they should be large enough to cope with eating baby brine shrimp.
  3. After a week, continue feeding the fry with baby brine shrimp. Tiny nematodes won’t offer enough nutritional value to the fry at this stage, so you can discontinue feeding them.
  4. At three to four weeks, you can continue feeding your fry with baby brine shrimp. Now you can also introduce very finely grated frozen foods, such as bloodworms and daphnia.

    We recommend using the Hikari brand, as all their frozen foods contain extra vitamins that are added before packaging. Also, the food goes through a strict decontamination process to remove parasites that could harm the fry.

  5. Once the fry reach four to five weeks of age, you can continue feeding brine shrimp but also introduce live blackworms and grindal worms. These aquatic worms are ideal for use as fry food because they can live happily in the tank until the fry eat them. It’s worth noting that adult bettas love blackworms and grindal worms too.
  6. When the fry reach eight to nine weeks, they are beginning to mature. Continue feeding your fry with live brine shrimp, aquatic worms, and frozen foods. Now, you can introduce dry pellet foods too.

As the fry continue to grow and will happily eat dry food, you can reduce the number of feedings to twice per day until the fry are fully grown.

Product and Portions

Many successful breeders recommend feeding live and frozen foods to improve the overall health and condition of their bettas, which all help to contribute to more rapid growth and bigger size at maturity. Large quantities of high-protein live food together with big water changes are proven to accelerate the growth of betta fry.

The food you feed your fry should correspond directly with the size of your fish. Feed your fry several times each day and offer the fish the largest food that will fit into their mouths. That regime, in conjunction with large daily water changes, produces large, full-sized, showy betta fish in a fraction of the time that other methods do.

When to separate the fry

Once the fry reach eight to nine weeks of age, they will begin to show their colors. At this age, males will begin to start nipping and showing early signs of aggression. So, now is the time to separate the fry into their own containers or tanks in a process known as “jarring.”

Each male fry will need his own container, which can be a bottle, cup, jar, or another container. Females can also be moved, although they can be kept together in a tank. However, you should know that larger fish will probably eat their smaller siblings.

Maintaining the jars can be a rather big job, depending on how many you have. An easy way of maintaining the temperature in all the jars is to place them all into a large tub of water with one heater in the tub. Remember that you must change the water in each jar daily, just as you did for the grow-out tank.

Final thoughts

Growing betta fry quickly can be achieved, but it is a time-consuming job that requires dedication and diligence. However, breeding bettas can be a very rewarding hobby, and you can finish up with some glorious color combinations from your home-bred specimens.

Once you’ve successfully grown-out your fry, you can trade or sell them through a local pet store, through friends, or to members of the online betta enthusiasts’ community. You might even want to show your best fish.

Although it’s not easy, the whole process of breeding betta fish is fun, satisfying, and ultimately extremely rewarding!

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