Do Aquatic Plants Need Oxygen?

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Caring for aquatic plants is slightly different from caring for land ones, but not by much.

All aquatic plants have similar requirements in terms of nutrients, lighting, humidity, CO2 and oxygen, and other factors that may play into their long-term wellbeing.

Today, we will discuss whether aquatic plants need oxygen and how much. For a plain and straightforward answer – yes, aquatic plants need oxygen.

Why do Aquarium Plants Need Oxygen?

Aquarium plants need oxygen to perform photosynthesis, but the answer is more complex than that. Plants eat up CO2 and produce oxygen during the daytime and consume oxygen to produce CO2 during the nighttime.

So, it’s safe to say that the plant’s physiological functioning depends strongly on the available environmental light.

In case of too much light, the plant will produce too much oxygen and consume too much CO2. This will cause the plant to deplete the CO2 levels in the tank, soon leading to nutrient deficiency and signs of death.

Excess oxygen is also responsible for algae bloom when correlated with other factors like excess lighting, improper nutrient distribution, etc.

If the plant doesn’t get adequate lighting, the plant will consume too much oxygen and flood the environment with too much CO2. As a result, the available aquatic life will begin to suffocate.

So, finding the right balance in this sense is critical to preserving your plants’ health and the system’s stability long-term.

Do Aquarium Plants Need Air Pump?

No, aquarium plants don’t necessarily need an air pump. That being said, the situation will necessarily differ from one case to the next.

Some circumstances will require you to invest in an air pump. One such case refers to heavily-planted aquariums.

While having a bunch of live plants in your aquarium is typically good, sometimes it can backfire. One of the roles of live plants is to oxygenate the environment during the daytime.

The more of them you have, the higher the oxygen levels in the aquarium. The problem is that plants reverse their physiological functioning in the absence of light, causing them to consume oxygen during nighttime.

A heavily-planted aquarium will become deprived of oxygen during the nighttime fast. The oxygen consumption effect will become even more severe if you have fish populating the aquarium.

In this case, the air pump may be necessary to provide both plants and fish with adequate oxygenation. Otherwise, nighttime plant activity may lead to severe oxygen deprivation, which could kill your aquarium life.

Do Aquarium Plants Make Oxygen?

Yes, aquarium plants make oxygen, but only during the day. They will consume oxygen during nighttime, and we’ve just discussed the slippery slope entailed by that.

Do Floating Plants Extract Oxygen from Water?

Yes, floating plants extract oxygen from the water. There’s really no difference between a rooted and a floating plant, except for the way they extract nutrients.

Rooted plants get their nutrients from the substrate via their rooting system, while floating plants extract them straight from the water column.

But both types get their oxygen and CO2 directly from the water.

Interestingly enough, all plants are extremely sensitive when it comes to lighting, influencing how they consume or produce oxygen.

Most people believe that the plant’s physiology changes during nighttime, but this is only partially true. In reality, it’s the absence of light that alters the plant’s functioning.

So, your plant will begin to consume oxygen whenever the light is too low. It doesn’t matter whether it’s nighttime or not. A cloudy day will cause the plants to go into oxygen consumption mode just as easy.

This is a reminder that you should be mindful of the tank’s lighting and oxygen levels in the long run.

Signs of Low Oxygen in Aquarium

Oxygen levels will drop in your aquarium for a variety of reasons.

These include:

  • Excessively warm waters – The hotter the water is, the less oxygen it will hold
  • Insufficient lighting, causing plants to consume oxygen rather than produce it
  • Too many fish and plants competing over the same space and consuming more oxygen than what’s being produced
  • Excess waste and dead matter, producing ammonia and nitrites and lowering oxygen levels

Naturally, you want to fix any oxygen-related problem fast because it can turn deadly at a moment’s notice. It all begins with identifying the signs of low oxygen, which you can achieve via assessing your fish’s behavior.

Some tell-telling signs include:

  • Low fish activity – Most fish will remain fairly energetic and active in a well-oxygenated environment. However, when oxygen levels drop, you will notice your fish moving way less. This is because movement forces oxygen-filled blood into muscles to support their activity. But if there’s not enough oxygen in the environment, the fish will try to preserve its energy and lower its need for too much oxygen. Oxygen deprivation will always cause fish to become more lethargic, which is a clear indicator that their oxygen intake is insufficient.
  • Rapid gill movement – Fish will move their gills more rapidly in an effort to pass more water through them. This will improve their oxygenation, but only mildly. They may also open and close their mouth rapidly for the same reasons.
  • Surface breathing – Occasional surface breathing is normal for labyrinth fish. These fish possess a labyrinth organ which they use to breathe atmospheric air at the tank’s surface. Bettas are popular labyrinth breathers, and this evolutionary feature has allowed this species to thrive in even the murkiest and muddiest waters available. However, surface breathing isn’t typical behavior for fish without a labyrinth organ. Fish often go to the water’s surface to breathe because that’s where the highest dissolved oxygen concentration is. If they do that, it clearly means there isn’t enough oxygen for them in the tank’s lower layers.

If your fish exhibit signs of low oxygen or suffocation, you need to act immediately. The situation will go south fast if you don’t.

What do Aquarium Plants Need?

Oxygen aside, aquatic plants have several other requirements to grow and develop properly.

These include:

Adequate Lighting

All plants require proper lighting, no matter their size, species, or favorite habitat. The problem is that these light requirements will vary from one plant to the next.

When it comes to figuring out the ideal lighting conditions for your aquatic plants, consider the following:

  • The light’s intensity – 10-40 lumen per liter of water, depending on the plant’s requirements.
  • The light’s duration – Plants need at least 8 to 10 hours of light per day
  • The color spectrum that will optimize plant growth and health – Go for a red and blue light spectrum for your aquarium plants. This isn’t vital, but it will optimize plant growth and boost your plants’ coloring considerably.
  • The type of light bulb to use – LEDs are the best choice given their energy efficiency and low heat exchange.
  • How to tell whether there’s too much or too little light – If you notice signs of algae bloom, that’s a sign of excessive lighting. If your plants display yellowing or browning leaves, the light is insufficient.

Lighting is among the most defining factors because it correlates directly with the plant’s ability to extract nutrients from its environment.

Proper Substrate

Enriched soil is naturally the best choice in terms of a substrate for rooted plants. This type of substrate provides great anchoring support and offers steady reserves of nutrients for plants to use long-term.

That said, sand and gravel look better, so most aquarists prefer these to the soil.

The problem is that both sand and gravel are considered inert substrates. In other words, they have no nutritional value for your plants. They also offer poor anchoring.

So, if you’re going for sand or gravel, be mindful of the downsides and work to overcome them.

This means you need to provide plants with fertilization and anchor them yourself until they stabilize themselves in the substrate.

CO2

All plants require CO2 during the day as part of the photosynthesis process. If there isn’t enough CO2, your plants won’t be able to perform photosynthesis and will experience nutrient deficiencies. Always assess your tank’s CO2 levels to prevent that.

Adequate Space

I understand the reasoning behind ‘the more plants, the better.’ The problem is that this is only true to a point.

Having too many plants in the same aquarium will inevitably lead to nutrient competition, and not all plants will survive the battle.

It’s also worth noting that a heavily-planted aquarium will also experience oxygen deprivation during nighttime.

Make sure you plant your aquarium wisely and resist the temptation of creating a small aquatic jungle in your tank.

Fertilization

Fertilization is necessary for both rooted and floating plants. You use root tabs for rooted plants and liquid fertilizer for floating ones. Keep in mind, balance and moderation are essential in this sense.

Excess use of liquid fertilizer promotes algae overgrowth, which comes with a wide range of problems.

Conclusion

Most aquatic plants are extremely hardy and will cope with any environmental conditions. That being said, they do need specific oxygen, nutrient, temperature, and lighting parameters to thrive.

Always be mindful of your plants’ oxygen needs because these organisms are essential in charge of the system’s chemical balance as a whole.

This means that whatever affects plants will inadvertently affect the rest of the aquatic life.

avatar I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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