Do Betta Fry Need Oxygen And Light?

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Betta fry are fascinating creatures. But they also raise a lot of questions for many aquarists. When it comes to aquarium equipment, most fish owners wonder whether they require oxygen devices or lighting. So, after years of experience, I’m ready to share what I know.

Betta fry require oxygen from 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.

For those of you who are in a rush, my personal recommendation for oxygen is the Lefunpets Sponge Filter (link to Amazon). You can go with anything you’d like when it comes to lightning, as long as the intensity and duration are correct.

Three weeks old betta fry swimming freely next to a lighting source.

Still curious? Feel free to check my complete guide on betta fish fry, where I discussed how to care for betta fry, what they eat, their growth stages, what equipment to use, and much more.

Do Betta Fry Need Oxygen?

Every living creature requires oxygen. Admittedly, bettas are unique. Most fish species cannot breathe the air in the atmosphere. They rely on gills that extract oxygen from the water. This is why fish die when they fall out of a tank.

But bettas have an advantage, a labyrinth organ that allows them to extract oxygen from the air and direct it into the bloodstream.[1]

Because of this labyrinth organ, bettas can survive in rice paddies, ponds, and other shallow water bodies with poor oxygen levels.

This is not an excuse to keep your bettas outside the tank. They can survive outside the water for longer periods than other species, especially if their bodies are moist. But if you prolong their time outside the aquarium, they will die.

Betta fry are complicated. You cannot afford to treat them like their adult counterparts. It can take between three and six weeks for betta fry to develop their labyrinth organs.

As such, you cannot expect baby bettas to survive the same oxygen-deficient conditions that adult bettas can tolerate. 

Fortunately, there are ways to improve an aquarium’s oxygen concentration. Following the tips below, possibly 90 percent of your betta fry will survive:

1. Air Pumps & Sponge Filters

Air pumps are tricky. You should add them to adult betta tanks. Adult bettas do not need air pumps.[2] But you will have difficulty maintaining the oxygen levels without one.

Air pumps shouldn’t be your first choice where breeding tanks are concerned. First of all, bettas thrive in slow-moving water. Secondly, air pumps have a reputation for generating strong currents. 

You can adjust the devices to accommodate a betta fry’s needs. But you are better off using a sponge filter, so long as the pores are too small to suck in the baby bettas.

You should only use air pumps when the need arises, for instance, if you add medication that consumes oxygen or if the ambient temperature is too high. 

Hot water holds less oxygen than cold water. Therefore, if the ambient temperature is causing the aquarium temperature to skyrocket, you can install an air pump to prevent the oxygen levels from falling.

When it comes to a betta fry tank, I personally recommend the Lefunpets Sponge Filter (link to Amazon). It was designed for tanks that hold small creatures, including betta fry and shrimp.

Three weeks old betta fry swimming in their aquarium.

2. Wide & Shallow Tanks

Try picking a wide and shallow breeding tank, which is 8 to 10 inches in depth. Fish respond to oxygen deficiencies by rushing to the surface where the oxygen concentration is highest. 

Therefore, if you have a shallow tank, the betta fry do not have a large distance to cover to reach the surface.

Additionally, your filter is more likely to distribute the oxygen evenly if the tank is wide and shallow. On the other hand, oxygen-deficient pockets can form at the bottom if you have a narrow and deep tank.

If your tank is wide enough, you can go without a sponge filter. You will probably see your betta fry swimming in the upper section, which is more oxygen-rich. That shouldn’t worry you; that is how they behave.

3. Live Aquarium Plants

How many plants do you have in the aquarium? This is a valid question since plants absorb CO2 and produce oxygen. Tanks with dense foliage are less likely to develop oxygen deficiencies.

You can experiment with any species that suits you, as bettas do not eat plants. Therefore, you don’t have to worry about the creatures destroying the foliage. 

However, you need a proper day/night cycle. Plants will consume oxygen in the dark. If you don’t have ample lighting, the plants could reduce the oxygen levels. That brings us to the second part of this article.

4. Clever Water Changes

Another great way to increase the oxygen levels in your tank is to do the water changes right. Just like any other fish, betta fry require water changes. 

Those can range from 25 percent twice a week to daily smaller water changes.[3] It mainly depends on your tank’s condition and the water quality.

Make sure you pour the water from a high point during the water changes. That will create aeration and dissolve oxygen into your tank.

Recently born betta fry that are still hung to their bubble nest.

Do Betta Fry Need Light?

Yes, betta fry need light. Bettas originate from tropical regions with plenty of sunlight.[4] The best way to maintain a fish’s health is to recreate the conditions it encounters in the wild, including sunlight. 

Keep the following in mind:

1. Artificial Lighting vs. Sunlight

Bettas in the wild use the sun to meet their lighting needs. But professional aquarists usually discourage beginners from using sunlight to illuminate an aquarium. First of all, you cannot control the sun, nor can you predict it. 

Bad weather can hide the sun behind a blanket of clouds for weeks at a time. If you don’t have artificial lighting, you will deprive your baby bettas of the light they need during that period.

Secondly, artificial lighting allows you to adjust the intensity. Direct sunlight can raise an aquarium’s temperature unexpectedly. This makes your aquarium vulnerable to algae infestations.

Algae continuously plague people that have positioned their tanks next to an open window. Artificial lighting gives you options. 

2. How Long Should You Keep The Lights On

Try creating a regular day/night cycle. The goal is to mimic the day/night cycle in the wild. Give the fry eight to ten hours of daylight. 

A day/night cycle also benefits the plants because they need light. Either way, do not leave the lights on 24/7. That will stunt their growth and make your foliage go wild.

3. Betta Fry Need To Sleep

You should avoid excessively bright lights and continuous lighting. Betta fry require standard aquarium lighting; they don’t have any special lighting requirements.

However, the lights can’t be too bright. Otherwise, the stress they induce will kill the betta fry. Sleep is a significant factor that newcomers rarely consider. 

Fish don’t have eyelids, and therefore, they have no way of blocking out the light if they want to sleep. Fish do not require complete darkness to rest.

However, they experience a certain amount of darkness in the wild, and they associate the absence of light with rest.

If you’ve ever observed a betta’s behavior over 24 hours, you noticed that the creature was very active during the day. Once the lights went out, it became lethargic. 

Betta fry are the same. Continuous light will overstimulate the creatures, inducing stress and anxiety. Depending on the size and age of the bettas, they may develop violent tendencies. Sleep deprivation is a danger to most sentient creatures.

4. Excessive Lighting Can Raise The Temperature

Direct sunlight can raise the temperature, but so can artificial lighting.[5] If the lights are too bright, or if you’ve kept them on continuously, the baby bettas will die. They cannot survive the temperature spikes that tend to occur in such situations. 

5. What Lighting Should You Use

Again, betta fry require standard lighting. Any model that works on your community tank will accommodate the breeding tank. Some people like fluorescent bulbs. Others prefer LEDs. 

Your selection doesn’t matter as long as the duration and intensity are appropriate. You can experiment with colored lights as well. They won’t hurt the bettas.[6]

It is common to include a timer, especially if you have a busy schedule. The timer will dim and then switch the lights off in your absence.

In case you still feel uncertain, here is a beautiful Youtube video that will take you through the process of growing betta fry from day zero to six weeks:

If you found this article helpful, these may also interest you:

Pro tip: If your betta fish breed frequently, you probably need to know a little about their eggs. You can find my complete guide on that topic here.


Because betta fish fry are still young, their labyrinth organ isn’t developed. Combining that with the fact that they are born in high volumes, it becomes pretty obvious that they’ll require more oxygen than adult fish.

That is why I suggest getting a sponge filter. Those devices create proper aeration and do not allow the tiny betta fry to get sucked in.

You have more choices when it comes to lighting. You can go with anything like LEDs and fluorescent bulbs. It is more crucial that you limit the duration to 10 to 12 hours. Allow the betta fry to sleep at night by switching the lights off.