1. How to Recognize Low Oxygen Levels?

• Fish constantly staying near the water surface or close to the air stone

• Rapid gill movements and gasping behavior

• Lethargy, loss of appetite, and tendency to sink to the bottom

• Behavioral disorders that become more noticeable, especially in the morning

1. Elements That Provide Oxygen in an Aquarium

• Surface movement: Filter outlets creating ripples on the surface increase oxygen exchange.

• Air pumps and air stones: They don’t provide direct oxygen but improve surface contact, indirectly contributing.

• Live plants: Produce oxygen during the day through photosynthesis.

• Water changes: Regular water changes supply fresh, oxygen-rich water.

1. How to Maintain Balanced Oxygen Levels

• Direct the filter outlet toward the surface to increase surface movement.

• Use an air stone to enhance water circulation and surface contact.

• Keep lighting regular and sufficient in planted tanks so plants can produce oxygen during the day.

• Perform weekly 20–30% water changes to balance water quality and oxygen levels.

• Avoid overfeeding; leftover waste increases bacterial activity that consumes oxygen.

1. Is Excessive Oxygenation Harmful?

• Although rare, too many bubbles can cause gas embolism in fish.

• This usually occurs when powerful air pumps run uncontrolled in small tanks.

• In balanced systems, it generally doesn’t pose a problem.

1. Beware of Oxygen Drops in Summer

• As water temperature rises, oxygen solubility decreases.

• During hot days, increase air stone usage and surface agitation.

• Once the aquarium temperature exceeds 28°C, oxygen levels may drop to critical levels.

• If necessary, use fans or aquarium cooling systems.

Conclusion
Oxygen level is one of the most vital parameters in an aquarium. With the right equipment, regular maintenance, and careful observation, it is possible to maintain this balance. Remember, oxygen is not only essential for fish but also for all aquarium inhabitants to live healthily.