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Betta Fry 101: Care, Tank Setup, Stages, Food & More

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Even after years of experience, I admit that dealing with betta fish fry can be challenging. That is especially true for new aquarists, as betta fry are pretty gentle and have different needs than adults.

So, after quite some time of learning from mistakes, I decided to gather some of the most frequent questions into one complete guide. In most cases, I will link to another article that I wrote so that you get the picture more thoroughly. 

Ultimately, in the last part of this article, I will list some essential tips to help you care for your betta fry. I will also include my personal gear recommendations.

So, without further ado, let’s dive into it.

For those of you who are in a rush, here is a table that gathers some of the most crucial information on betta fish fry:

FoodInfusoria
Feeding frequency4-5 times a day
When to separate8 weeks of age
Water depth8-12 inches
Survival rateUp to 90%
Tank size10 gallons
Growth duration5 months
Temperature85-88° F
pH7.0-7.2
General hardness2-20 dGH
Carbonate hardness3-5 dKH
Ammonia0 ppm
Nitrites0 ppm
Nitrates<20 ppm

What Do Betta Fry Eat?

What you should feed your betta fry depends mainly on their age. For your convenience, here is a table that gathers what they should eat at different ages:

InfusoriaUntil they reach day 7
Baby brine shrimpFrom day 7 to 21
Freeze-dried/frozen foodsFrom day 21 and beyond
BlackwormsFrom week five and beyond
Dry pelletsFrom week eight and beyond

When they are born, betta fry cannot eat large pieces of food as they won’t fit in their mouths. That is why people usually feed them infusoria, which is microscopic.

Because it takes time, it is best to culture the infusoria before the fry are born. This way, you can introduce it immediately after they hatch.

After seven days, the fry should be large enough to eat baby brine shrimp. I personally used the Ocean Nutrition Instant Baby Brine Shrimp (link to Amazon)

The fry should eat four to five times a day until the 8th week, preferably in small portions. Just make sure to perform regular water changes, as I’ll explain later.

Still curious? Click here for more information on what betta fry eat. Included some visual videos that show you how to prepare their meals properly.

Do Betta Fry Need Oxygen And Light?

Betta fry need oxygen-inducing devices like sponge filters and air stones, as their labyrinth organ is not yet developed. They will also need lighting to create a healthy day and night cycle, approximately 10-12 hours a day.

Adult betta fish can live without water aeration as their organs are fully developed. But betta fry are more sensitive to oxygen deficiencies, so an airstone or a filter is needed.

Make sure you pick a sponge filter that won’t suck up your fry. Regarding the lighting schedule, make sure you turn off the lights at night.

Like any other fish, betta fry do not have eyelids, and excessive exposure to light will stress them. You should also avoid placing the tank next to a window.

Caught your attention? Click here for more information on whether betta fry need oxygen and light. I also included my personal filter recommendation.

How Deep Should The Water Be For Betta Fry?

The water depth should be between 8 to 12 inches. Generally, it is better to have a broad and shallow tank than a narrow and deep one. That is because betta fry swim horizontally, and shallow tanks make it easier for them to do so.

Many aquarists keep their adult betta fish in a show tank, which is typically tall and narrow. But these types of tanks are harmful to betta fry.

To grow properly, they need space to swim horizontally. Also, broad tanks dissolve oxygen more efficiently, as they have more surface area. And as mentioned earlier, oxygen is critical for newborn betta fry.

Wish to learn more? Click here for more information on how deep the water should be for betta fry. Besides listing all the advantages of broad tanks, I also shared the particular tank I used.

How Long Do Betta Fry Take To Grow?

It takes up to five months for betta fry to grow and reach full size. At this point, they are considered adults and have fully functioning organs. However, only at the age of seven months will the betta reach sexual maturity.

Your betta fry will grow rapidly in the first couple of weeks. Then, the growth pace will gradually decrease. That is perfectly normal, so don’t worry about it.

Bear in mind that some bettas will reach their full size after three months. That mainly depends on their feeding schedule and genetics.

Sounds interesting? Click here for more information on how long it takes for betta fry to grow. In there, I provided some practical tips to make your fry grow faster.

What Are The Betta Fry Growth Stages?

Here is a table summarizing the betta fry growth stages:

StageAgeSize (inches)
EggDays 0-3<0.10
NewbornDays 3-7~0.10
JuvenileWeeks 1-30.15-0.35
YoungMonths 1-30.35-1.40
AdultMonths 3-52.00-3.00
Stage 1: betta fish fry that are still growing in their eggs.
Stage 2: two-day-old newborn betta fry feeding on their yolk sac.
Stage 2: three-day-old newborn betta fry; some are now free swimmers.
Stage 3: three-week-old juvenile female betta fry.
Stage 4: two-month-old young betta fry, 1 inch in length.
Stage 5: fully grown adult male betta fish, collecting eggs into its bubble nest.

The betta fry starts its life in an egg, which typically takes three days to hatch. Then, the fry will hang vertically, still attached to the bubble nest. It will feed on the yolk sac at this point.

After three to seven days, the newborn fry will detach from the bubble nest and become free swimmers. As they start swimming horizontally, you should take out the father before he eats them.

Still curious? Click here for more information on the betta fry growth stages. I also included some valuable pictures that will help you identify the particular stage of your betta fry and embedded a beautiful Youtube video that shows their entire development, step-by-step.

How Long Can Betta Fry Live Together?

Betta fry can live together for approximately eight weeks. After that, it is better to separate them before they start fighting. Generally, betta fry can live longer together if they have enough hiding spots and room for swimming.

After they hatch from their eggs, betta fry do not pose a threat to one another. They can live together peacefully for about two months.

Of course, if you notice hostility earlier than that, you should separate them immediately. I personally recommend adding hiding places from month one and beyond.

Caught your attention? Click here for more information on how long betta fry can live together. In there, I embedded a helpful video that shows how to transfer them into a new tank properly.

How Many Betta Fry Will Survive?

Approximately 90 percent of the betta fry should survive given the right conditions. These include a stable temperature of 85 to 88 degrees F and a pH of 7.0 to 7.2. It is also essential to remove the adult fish in time and provide enough hiding places.

Many fish owners find it hard to believe that the survival rate of betta fry is so high. But in fact, those little creatures are pretty hardy. All you have to do is keep them in a suitable environment.

The most important thing is to remove their parents in time. The mother should be taken as soon as she’s done secreting her eggs. The father, on the other hand, is less problematic.

After the eggs are laid, he will take care of them until the fry hatch. And even then, he will protect the fry and ensure they grow properly.

But when the fry become free swimmers (usually after 48 to 72 hours), the male betta fish will start showing hostility signs. Therefore, I suggest taking the father out as soon as the first fry starts swimming horizontally.

Wish to learn more? Click here for more information on how many betta fry are expected to survive. Besides discussing their survival rate, I listed the essential steps you should take to bring this number to the maximum.

Why Are My Betta Fry Dying?

If your betta fry die in high numbers, these are usually the reasons:

  • The water parameters are wrong or unstable.
  • There are toxins in the water, such as ammonia and nitrites. 
  • The water changes are too aggressive. 
  • The fry were overfed or underfed. 
  • The tank wasn’t cycled properly.

As mentioned earlier, under ideal circumstances, about 90 percent of the betta fry should survive. Therefore, if you lose them in large batches, something is wrong.

As a first step, I suggest measuring the water parameters, including the pH, ammonia, nitrates, and nitrites. I personally use the API FRESHWATER MASTER TEST KIT (link to Amazon) for that.

Aim for the water parameters mentioned at the beginning of this article. If any of the parameters is out of range, fixing it with a water conditioner is better than conducting a significant water change. That will create less stress.

Sounds interesting? Click here for more information on why betta fry keep dying. In this article, I take you step-by-step on solving that issue and achieving the desired 90 percent survival rate.

Why Are My Betta Fry At The Bottom?

Newborn betta fry naturally sink to the bottom of the tank as they cannot yet swim properly. But once they become free swimmers (days 3-7), betta fry may stay at the bottom due to water issues, such as swinging temperatures and toxins.

Many fish owners get nervous when they see their betta fry at the bottom. That is understandable, as this behavior usually indicates that a fish is suffering.

But newborn betta fry are different than adult fish as they haven’t developed yet. Therefore, they aren’t capable of swimming to the upper sections.

After a week, your betta fry should leave the bottom of your tank. If they don’t, you should check the water conditions to see if something might be stressing them.

Still curious? Click here for more information on why betta fish fry stay at the bottom of the tank. In this article, I explained how to distinguish a natural behavior from an actual underlying illness.

What To Do With Betta Fry?

These are the general steps you should follow after your betta fry hatch: 

  1. Leave them in the tank with the father until they start swimming horizontally. 
  2. Remove the male betta fish once they become free swimmers. 
  3. Feed them microorganisms such as baby brine shrimp and infusoria. 
  4. Feed the fry 4-5 meals a day until they are two months old.
  5. Make sure the water parameters remain stable.

These are the general steps most aquarists should take once they realize they are about to face a batch of newborn betta fish fry. 

Caught your attention? Click here for more information on what you should do with betta fry. There, I wrote in detail what you should do in each step.

How Do I Take Care Of Betta Fry?

Betta fry are more challenging to care for than adult bettas because they are smaller and more delicate. But if you can keep adult bettas alive, you can raise betta fry. 

The key is to keep the following in mind:

1. Considering The Tank Size

Most aquarists do not keep betta fry in a small tank. They know that crowded conditions will hurt the babies, stunting their growth or killing them.

Despite what many people think, fish cannot adjust their size to fit the tank size.[1] Instead, crowded conditions induce stress which, in turn, debilitates the fry’s growth rate, especially in situations where the babies have stopped eating.

Studies have found that small water bodies encourage the production of hormones like GABA (Gamma-aminobutyric acid) that inhibit growth in goldfish.[2]

In other words, the fish is not necessarily choosing to alter its growth rate. If stressful conditions persist and the babies survive, they may develop illnesses with long-term consequences. 

But competent aquarists are unlikely to keep betta fry in crowded conditions. The bigger question is whether they will keep the babies in the grow-out tank from the start or move them later on.

Betta eggs are just 0.03 inches in diameter.[3] You can keep them and the fry that eventually hatch in tanks as small as 5 gallons.[4] But I personally suggest picking a 10-gallon tank.

But eventually, the fry will grow. To prevent them from crowding the nursery, you have to send the babies to a grow-out tank after a few weeks.

Neither option is superior. You won’t harm the babies by keeping them in the grow-out tank from the start or transferring the creatures later on.

Although, fish hate change and you risk shocking the betta fry by moving them to a bigger tank and forcing them to grow accustomed to a new environment.

Then again, if you acclimate the babies appropriately, they will survive the transition. Beginners are better off using a grow-out tank from the start. 

  • If you feel unsure about it, here is an excellent Youtube video that shows how to move betta fry into a grow-out tank:

2. Adjusting The Water Conditions

A grow-out tank will do more harm than good unless you adjust the parameters to fit the betta’s needs. These variables have a direct impact on an adult betta’s biological processes. 

The wrong parameters can have disastrous consequences for betta fry because they are smaller and more vulnerable. 

Keep an eye on the following:

  • pH

The pH is concerned with the acidity of the water. An article in the International Journal of Chemical Studies found that most freshwater species required a pH of 6.5 to 9.0 to thrive.[5] 

They also noted that the pH influenced the growth and mortality rates of fish, not to mention their ability to resist diseases. 

From my experience, the optimal pH for betta fry is 7.0 – 7.2. Test this variable routinely and take the necessary steps to alter any errors you observe gradually.

For instance, you can raise the pH by changing the water, increasing the aeration, applying baking soda and shells, etc.

Peat moss, driftwood, and higher carbon dioxide levels will do the opposite. They will lower the pH.[6]

These methods only matter to people that want to alter the pH using organic techniques. But it is easier to rely on chemical products. The market has a multitude of water conditioners that can raise or lower the pH.

To make life easier, I personally recommend getting the API PROPER pH 7.0 Stabilizer (link to Amazon). This product stabilizes the water and sets the pH to a neutral 7.0.

  • Hardness

Many people ignore the hardness even though studies have found that the variable affects the growth rate.[7]

The hardness is concerned with the concentration of minerals in the water. Bettas require soft to medium hardness.[8]

Try aiming for these two values:

  1. General hardness: 2-20 dGH (70-300 ppm)
  2. Carbonate hardness: 3-5 dKH (55- 90 ppm) 

Measuring these is relatively easy with the API GH & KH TEST KIT (link to Amazon). But frankly, almost all kits measuring these two parameters are acceptable.

If the water hardness is wrong, it is usually because the water is too hard (especially when using tap water). Here is a video that shows how to fix it:

  • Temperature

Bettas are just as sensitive to changes in the temperature as they are to the pH. Experienced aquarists will encourage you to keep the water at 85-88° F (29-31° C). 

But you don’t have to maintain that exact temperature, as any temperature between 75-88° F (24-31° C) will do. But you can raise the temperature as high as 88 degrees F to optimize the growth of the fry.

Keep an eye on the heater. This assumes that you have a heater. Some people rely on the ambient temperature, but that is only possible if the weather in your region is conducive for bettas. 

Even if your location has plenty of sunlight, you cannot trust the ambient temperature to remain the same. 

What if it rains for the next few weeks? The baby bettas will not survive once the temperature in the water plummets. You may also develop the opposite problem. 

The ambient temperature may climb. If you have to position the tank next to the window to keep the temperature within the appropriate range, the water could overheat in your absence.

That is not your only concern, as the direct sunlight will cause the algae to bloom. Professionals in the business will encourage you to move the aquarium away from the window. 

But if the ambient temperature keeps falling because of erratic weather conditions, you may feel compelled to place the tank near the window to prevent the temperature from dropping.

A heater eliminates all those concerns. You can position the aquarium in any room you like, away from the window. Artificial lighting can provide the same benefits the betta fry would typically acquire from the sun. 

And if the ambient temperature rises during the summer, you can turn the artificial lighting and the heater off. Simply put, a heater gives you more control.

3. Maintaining A Clean Environment

Keep the aquarium clean. Betta fry won’t survive in a dirty aquatic environment. They are just as vulnerable to ammonia spikes as their adult counterparts. 

Hygiene in a breeding or grow-out tank has two components:

  • Filter

Filters remove pollutants from the water. Technically speaking, you can do without one. But your tank is more likely to struggle with ammonia spikes. 

That is because fish fry have voracious appetites, and It won’t take long for leftovers and waste to chock the water.

The filter doesn’t stop at removing pollutants. It will also increase the gaseous exchange at the surface by agitating the water. But that raises a question. What if the filter sucks the baby bettas in?

Some filters have a strainer sponge to prevent the intake tube from destroying the betta’s fins. But you cannot trust them to keep tiny fry out. 

Your only option is to use a sponge filter. If you prefer a stronger filter to prevent oxygen deficiencies, add more air stones.

If you don’t have one, I suggest considering the well-known Aquapapa Bio Sponge Filter For Betta Fry (link to Amazon). It is incredibly gentle and was specially designed for betta fry.

  • Water Changes

Change the water twice a week. Twenty-five percent is enough.[9] A more significant water change will induce stress in the babies because of the fluctuations it will generate in the water’s chemistry.

If the ammonia concentration concerns you, apply water conditioners. Don’t forget to vacuum the bottom. The leftovers and waste will sink to the substrate, where they will rot unless you remove them. 

4. Feeding The Betta Fry Properly

The babies won’t survive without food. You don’t have to feed them right away, as I mentioned earlier. Wait until they start swimming horizontally. The yolk sacs should have disappeared by that point.

Start by feeding them infusoria. Because of their small size, they need microscopic foods that can fit in their mouths. If you cultured infusoria in a separate jar, use a dropper to transfer the infusoria water into the betta tank:

Naturally, as the betta fry matures, its culinary needs will evolve. That forces you to introduce baby brine shrimp, blood worms, flakes, pellets, daphnia, and other appropriate food items to the aquarium.

They need as much protein as you can give them at this stage, which is why live foods are so important. That being said, manufacturers make commercial foods that can satisfy the creatures if you’re too busy to source your own worms and infusoria. 

But you should pay close attention to the information on the packaging. Make sure the commercial foods provide the nutrients the babies would typically extract from the organic meals. 

Whether you prefer organic or commercial foods, you have to feed the fry several times a day. Aim for four or five meals. 

Those are too many meals for adult bettas, but the fry are different. Underfeeding is a bigger issue for these creatures than overfeeding. 

Their voracious appetites are only problematic for negligent aquarists with poor maintenance routines. In the absence of a filter and regular water changes, you will overwhelm the tank with leftovers and waste.

5. Removing The Parents In Time

This goes without saying. Keep the parents away from the aquarium. Once the mother lays the eggs, you should move her to a hospital tank or the main aquarium. She doesn’t serve any purpose. 

The female betta will eat her offspring if you allow her to stay. You should only permit the mother and her babies to share a tank if you want to lower the betta fry population.

If you have a decent number of plants and decorations, some of the babies will survive. But the mother will find and eat the majority, preventing the offspring from maturing into adults and crowding your tank.

If you want the babies to survive, remove the mother. The father will look after the eggs, clean them, retrieve them whenever they fall out of the nest, and eat the unfertilized eggs before they can rot.

However, once the eggs hatch, you can also remove the father. He has no use at that point. If you let him stay, the male betta will snack on the babies. Take him away and raise the betta fry yourself.

My Recommended Gear For Betta Fish Fry

References

  1. https://injaf.org/the-think-tank/do-fish-grow-to-the-size-of-their-tank/
  2. https://cosmosmagazine.com/nature/do-goldfish-really-grow-to-the-size-of-their-tank/
  3. https://nippyfish.net/2017/09/27/betta-growth-from-birth/
  4. https://modestfish.com/how-to-setup-first-betta-fish-tank/
  5. http://eprints.cmfri.org.in/14760/1/International%20Journal%20of%20Chemical%20Studies_2020_Chhandaprajnadarsini%20E%20M_Significance%20of%20water%20pH%20and%20hardness%20on%20fish%20review.pdf
  6. https://www.ratemyfishtank.com/blog/properly-maintaining-the-ph-in-a-freshwater-aquarium
  7. https://bmcresnotes.biomedcentral.com/articles/10.1186/s13104-020-05382-x
  8. https://www.vivofish.com/betta-fish-care/
  9. https://bettasource.com/more-betta/breeding/power-growing-fry/