Do Aquarium Plants Need Oxygen: Reasons & Benefits

Many fish keepers have pond plants in their aquariums. And while they may seem like a simple addition, pond plants do require oxygen to survive. That’s why it is important to consider their needs when planning your aquarium setup.

In this article, we are going to find out the importance of oxygen for aquarium plants as well as its causes, benefits, and tips regarding aquatic plants that produce oxygen.

Do Aquarium Plants Need Oxygen?

Aquarium plants need oxygen to survive, just like fish. But unlike fish, they cannot extract oxygen from water. So while an aquarium with a pond plant is not a vacuum sealed system, the plants still require supplemental amounts of oxygen.

In addition, it is important to provide enough oxygen for the plants to be able to grow.

Why Do Aquarium Plants Need Oxygen?

The primary cause of aquatic plants requiring oxygen is photosynthesis – the process by which these plants create their food using light energy. Photosynthesis is a natural process that all plants undergo. It’s how they produce their food and make our air safe to breathe! But while photosynthesis is necessary for aquatic plants, supplemental oxygen is not only necessary but also beneficial.

Studies have found that supplemental oxygen promotes healthy growth in aquarium plants as well as increases their resistance to diseases and pests. Additionally, it has been proven to improve plant coloration (including shades of green and yellow), reduce the need for artificial light, and even stimulate new growth in some cases!

Free-swimming aquarium fish in a fish tank.

What Are the Signs of Low Oxygen in Your Aquarium?

The easiest way to determine if your aquatic plants require supplemental oxygen is by checking their water clarity. If the water appears cloudy or has a brownish tinge, then supplemental oxygen may be necessary. Additionally, you can also test your plants’ chlorophyll levels using a spectrophotometer. If they are low, supplemental oxygen will help them to recover.

Low oxygen can also cause several signs in your aquarium including:

  • Deterioration of the fish population
  • Weakening of the immune system in fish
  • Decreased plant growth rates and colors
  • Increased susceptibility to disease and pests
  • Low water clarity
  • Chlorophyll levels are low even when the light is fully on
  • Gasps of air from the plants
  • Lackluster colors and poor growth rates in fish
  • High levels of dissolved oxygen (DO) in the water, indicating excess aeration
  • A decrease in the number of aggressive or territorial fish
  • An increase in calm, passive fish
  • Accumulation of organic materials on the bottom of the aquarium

How to Measure Oxygen Level in an Aquarium?

Aeration of water in aquarium with different colored fishes and plants

Use an Oxygen Meter Kit

The Oxygen Meter Kit is a handy tool for testing the levels of oxygen in your aquarium. The kit comes with an oxygen meter, water sampling cup, and transfer tube, as well as for instructions on how to use them. When using the oxygen meter, it’s important to follow these guidelines:

Step 1

Fill the water sampling cup half full with fresh aquarium water and place it on top of one of your live plants. Leave enough room at the top of the cup so that when you press down on it, water is forced through the oxygen meter and into the cup.

Step 2

Make sure to hold still while pressing down on the water sampling cup; if you move around too much, bubbles may rise to the surface and cancel out some of your readings.

Step 3

After 30 seconds or so have elapsed, release all pressure from inside of the water sampling cup and read your meter’s reading. You should see a number that corresponds to the percentage of oxygen in the aquarium water. For example, if your meter reads at 12 ppm (parts per million), then 100% of the oxygen in the aquarium is present.

Step 4

If you notice any changes in your readings over time, be sure to take them again and compare them to what they were initially. This will help you track down and determine which areas or pieces of your aquarium require more oxygen to thrive.

What Causes Low Oxygen Level in an Aquarium?

There are a few potential reasons why your aquarium may be low on oxygen. We have listed the most common reasons here:

  • Excess aeration (fans, air pumps): high levels of DO can indicate that the aquarium is being over aerated and more oxygen is not required.
  • Poor water filtering: if filters are not effectively removing waste materials, these materials will accumulate and lower the amount of available oxygen in the tank.
  • Obstruction of anemones by rocks or plants: heavy objects can decrease circulation and restrict the exchange of oxygen and carbon dioxide.
  • Excess organic material: this can be from flammable food or plants, decaying plants, etc. This material can accumulate over time and lower the amount of oxygen available to fish.
  • Overstocking: Water quality issues (high levels of dissolved oxygen, low levels of pH, or electric conductivity) can be caused by overstocking, incorrect temperature and water chemistry, or overcrowding. Overcrowding can lead to the destruction of essential fish habitats and aggression/territorialism in fish.
  • High water temperature: water temperature can affect the level of dissolved oxygen in an aquarium. Warmer water temperatures increase the metabolic demand for oxygen by fish, while cooler water temperatures reduce the demand. High levels of dissolved oxygen can be caused by warm water fish, high levels of organic waste in the aquarium, or poorly maintained filters.
  • Stagnant water: Low levels of dissolved oxygen can be caused by stagnant water. Sediments and organic materials can accumulate over time, reducing the amount of oxygen available to fish. Additionally, stagnant water can promote the growth of harmful algae and bacteria.
  • Chemicals: Chemicals such as chlorine can contribute to high levels of dissolved oxygen in an aquarium. While approved for use in water supplies, chlorine may be detrimental to fish if used at high levels or for extended periods.

What Does an Air Pump Do?

An air pump is a small piece of equipment that helps aquarium plants get the supplemental oxygen they need. Air pumps are generally battery operated and come in a range of sizes to fit any aquarium. When turned on, the air pump creates bubbles that rise to the surface and carry oxygen down to the plants.

Closed up colorful home aquarium and air bubbles.

What Are the Benefits of Having an Air Pump in Your Aquarium?

Having an air pump in your aquarium can help to increase the level of dissolved oxygen in the water. Excessive levels of dissolved oxygen can be harmful to fish, and an air pump can help to bring concentrations back within acceptable limits. Here are the benefits of having an air pump in your aquarium.

  • Better filter system: Having a better quality filter will help to increase the level of dissolved oxygen in your aquarium. High-quality filters remove waste and debris, providing fish with more nutrients and clean water.
  • Keep aquarium oxygenated during emergencies: During a power cut, you can oxygenate your tank by using an air pump. This will help to increase the level of dissolved oxygen in the water and may help to protect fish from damage caused by low levels of dissolved oxygen.
  • Increased growth rates: An air pump can help to increase the growth rates of your aquarium plants. By providing them with supplemental oxygen, they will be able to grow larger and more vigorous than they would without an air pump.
  • Improved aesthetic: Having an air pump in your aquarium can improve the aesthetic appeal of your tank. By creating a bubble-like atmosphere, an air pump can create a stunning contrast with denser water layers.
  • Increased resistance to diseases and pests: Having an air pump in your aquarium can help to increase the resistance of your fish to diseases and pests. By providing them with supplemental oxygen, they will be better able to fight off disease and parasites.

What Types of Plants Oxygenate Tanks the Best?

Most aquarium plants will oxygenate your tank, but some are better than others. Here are among the most effective types of plants for oxygenating tanks!

  • Hornwort (Ceratophyllum demersum): Hornwort is one of the most effective plants for oxygenating tanks. This aquatic plant traps food particles in its leaves and absorbs sunlight to produce energy, which helps it photosynthesize. As a result, hornwort can help to increase the level of dissolved oxygen in your aquarium.
  • Eelgrass (Zostera): Eelgrass is another plant that can oxygenate your tank. This aquatic grass captures food particles in its leaves and funnels them to the roots, where they are absorbed into the soil. Additionally, Eelgrass has slimy blades that trap debris and provide fish with plenty of places to hide.
  • Java fern (Microsorum pteropus): Java Fern is another highly effective plant for oxygenating tanks. This aquatic moss traps food particles in its leaves and absorbs sunlight to produce energy.
  • Green Cabomba (Cabomba caroliniana): Green Cabomba is an effective plant for oxygenating tanks because it creates a slimy canopy that traps debris and provides fish with plenty of places to hide. Additionally, the leaves of this aquatic plant are covered in microscopic spines that help to remove pollutants from the water column.
  • Ludwigia repens (Ludwigia repens): Ludwigia repens is a slow-growing aquatic plant that can oxygenate your tank. This aquatic plant has heart-shaped leaves that trap food particles in its blades and absorb sunlight to produce energy. Additionally, Ludwigia repens produces stems topped with floating Ludwigia flowers. These flowers provide the aquarium with essential nutrients and help to purify water.