Everyone knows fish need oxygen to survive, but do you know how to oxygenate a fish tank without a pump?
There are many ways to oxygenate or aerate a fish tank without a pump, including pouring water from a height, adding ice cubes, changing large volumes of fish tank water, and manually stirring the aquarium water.
One question remains: how do you do it? Keep reading to learn proven tricks to add oxygen to a fish tank without having to shell out money for an air pump.
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What Causes Oxygen Deficiency in Fish Tank?
Low levels of dissolved oxygen in fish tanks can be due to the following reasons.
- Overcrowding – More fish in an aquarium translates to stiff competition for oxygen. Aquarists must observe the “one-inch-size-fish-per-gallon” rule.
- Too Many Fish Waste – Microorganisms like bacteria also require oxygen to break down organic compounds, such as uneaten fish food, fish poop, and other debris.
- Warm Water – Water temperatures higher than 86 degrees Fahrenheit reduce the water’s oxygen-holding capacity.
- Still Water – Stagnant water prevents the mixing of oxygen-rich surface water with oxygen-poor bottom water.
- Algae Overgrowth – Algae get oxygen in fish tank during their active respiration at night.
- Live Plants – Although live plants produce oxygen as a byproduct of photosynthesis, they consume oxygen when there is no light, such as at nighttime.
- Chemicals – Some water conditioners and fish medications can influence aquarium water’s oxygen-carrying capabilities. Aquarists must research these products’ active ingredients for their impact on dissolved oxygen.
Signs of Low Oxygen in Aquarium
The only way to know an aquarium has low oxygen levels is by testing it with a dissolved oxygen meter.
However, you can observe some tell-tale signs of low dissolved oxygen, allowing you to oxygenate the aquarium as necessary.
- Sluggish fish movements – Fish spend oxygen every time they move. Hence, you can suspect low oxygen levels if your fish is not moving as usual, even during meal times.
- Labored breathing – Fish will attempt to “breathe” in more oxygen by moving their gills faster (fish filter oxygen through their gills).
- Gasping for air – You will notice your fish going to the surface more frequently to get more oxygen in a fish tank. This sign indicates dangerously low oxygen levels.
Ways to Oxygenate a Fish Tank Without a Pump
What is the Difference Between Oxygenation and Aeration?
The main difference between oxygenation and aeration is their oxygen levels. Atmospheric air contains 21% oxygen (and 78% nitrogen). Hence, aeration only introduces about 21% oxygen into the fish tank.
Meanwhile, oxygenation delivers up to 99% oxygen into the aquarium water. Most aquarists make a oxygen pump for fish tank units to provide the water with such a high percentage of oxygen.
Another difference is that aeration prevents algae overgrowth, regulates water temperature fluctuations, and improves water quality.
On the other hand, oxygenation is most suitable in low levels of dissolved oxygen that can undermine fish health and safety. It can also stimulate growth and feeding in sick fish.
How do I test for my fish tank’s dissolved oxygen levels?
You have two ways to test oxygen levels in fish tank units.
First, use a dissolved oxygen test kit, similar to a pH test strip. You only need to add a few drops of aquarium water on a test strip, wait for it to change color, and compare the color to a baseline chart.
Second, use a dissolved oxygen meter (like a pulse oximeter). Dip the probe into the fish tank water and read the oxygen levels on the screen. This method is more accurate than the dissolved oxygen test strip, although it is not maintenance-free.
Is too much oxygen harmful for fish?
The recommended level of dissolved oxygen for fish tanks is six to eight milligrams per liter or about 0.35 to 0.47 grains of oxygen per gallon. The average oxygen saturation is 80 to 110 percent. Any value above these figures is harmful, causing “gas bubble disease.”
To be specific, excess oxygen (and nitrogen) form microbubbles in the fish’s blood vessels, coalescing to produce larger bubbles. These air pockets can obstruct blood flow, leading to tissue and organ damage, as well as possible death.
You have several options on how to oxygenate a fish tank without a pump.
Short-term solutions include pouring fish tank water from a height and replacing 50% of the aquarium water with fresh water. Adding ice cubes, manually stirring the aquarium water, and directing airflow to the fish tank also help.
Although these tricks are suitable for instant oxygen spikes, a better approach is to install a power filter or spray bar to ensure long-term oxygenation adequacy.