Having an aquarium full of vibrant, healthy fish is an enjoyable hobby for many people. Watching the fish swim gracefully through the water can have a calming effect. However, keeping an aquarium requires proper equipment to maintain a healthy environment for the fish. One piece of equipment that is not always necessary is an air pump.
What is an Air Pump?
An air pump is a device used to pump air into the tank water. This serves several purposes:
- It agitates the water surface, allowing for gas exchange. This introduces more oxygen into the water for the fish to breathe.
- The bubbles provide water circulation, preventing stagnation. Stagnant water can become depleted of oxygen.
- The water movement helps dissipate carbon dioxide produced by fish and plants. Too much carbon dioxide buildup can be harmful.
So in summary, an air pump oxygenates and aerates the water to support aquatic life. However, some fish can get by just fine without an air pump’s added oxygenation and water circulation.
Why Some Fish Don’t Require an Air Pump
Certain fish have adapted in ways that allow them to thrive in tanks without an air pump:
Fish like bettas and gouramis have a special labyrinth organ that enables them to breathe oxygen directly from the air. They can come to the water’s surface and take gulps of air. This supplemental breathing allows them to survive in low-oxygen water conditions.
Air Breathing Fish
Some fish like paradise fish have a specialized swim bladder that functions like a lung, allowing them to breathe air. They will swim to the surface periodically for a gulp of air. This adaptation means they don’t rely solely on dissolved water oxygen.
Zebra danios and other minnows can absorb oxygen directly through their skin and fins. The large surface area of their fins allows for sufficient gas exchange without the need for high dissolved oxygen levels.
Low Oxygen Tolerance
Certain fish have a higher tolerance for lower oxygen concentrations in the water. Catfish and goldfish, for example, can withstand lower oxygen environments than other fish.
So an air pump is not essential for survival for fish with adaptations that allow alternate oxygen intake. However, additional considerations exist when keeping these fish without an air pump.
Keeping Fish Without an Air Pump
While the following fish can survive without supplemental aeration, there are some care guidelines to follow:
- Perform regular partial water changes to replenish oxygen and reduce waste buildup.
- Include live plants to produce oxygen through photosynthesis.
- Minimize stocking density to prevent oxygen depletion from overcrowding.
- Use a filter to maintain adequate water circulation and gas exchange.
- Monitor water parameters like oxygen levels to ensure they remain acceptable.
- Supplement with an air pump if signs of oxygen deficiency arise.
So more care and vigilance are required when keeping fish without an air pump. But it certainly can be done successfully! Let’s look at some examples of fish that do quite well without added aeration.
Fish That Can Live Without an Air Pump
Here are some of the most popular varieties of fish that can live healthy lives without the aid of an air pump:
The Siamese fighting fish, or betta, is undoubtedly one of the most popular for homes and offices. Their long, flowing fins and brilliant colors make them extremely attractive. Bettas hail from stagnant rice paddies and slow moving streams in Thailand. As labyrinth fish, they can breathe oxygen from the air when needed. This makes them ideal for living in low-oxygen environments like small bowls or vases, though larger tanks are still preferable. Make sure any betta tank includes plenty of plants and a filter for waste removal.
Paradise fish are a close relative of bettas, hailing from slow moving waters in parts of China and Korea. They also have a labyrinth organ that allows them to breathe air. They can survive for months in a vase without an air pump! Like bettas, they should still be kept in a filtered tank of at least 5 gallons. Paradise fish are naturally aggressive, so they should not be housed with other fish unless breeding. Their beautiful fins and coloring make up for their aggressive attitude.
The various types of gouramis are another labyrinth fish well suited to low oxygen environments. Dwarf gouramis like honey and flame gouramis only grow to about 2 inches long, making them perfect for small, unfiltered nano tanks. Larger gouramis like opaline and pearl gouramis reach 4-6 inches, requiring at least a 10 gallon filtered tank. All gouramis occasionally swim to the surface to gulp air thanks to their labyrinth organ. This allows them to thrive without an air pump.
Fancy goldfish with bulbous bodies and flashy colors are popular ponds and aquarium fish. They can survive for short periods in low oxygen conditions. However, an air pump is still recommended for goldfish tanks to promote proper waste breakdown. Without adequate oxygen circulation, toxins can accumulate from goldfish wastes. Goldfish kept without an air pump will require very frequent water changes. So air pumps are still advised for maintaining water quality with messy goldfish.
These lively little striped fish dash around tanks in constant motion. Zebra danios are very hardy fish that can withstand a wide temperature range. Thanks to their small size and cutaneous breathing, they require little dissolved oxygen to thrive. A group of 6 danios can easily survive in a 10 gallon filtered tank without an air pump. Overcrowding should be avoided, as too many danios increase waste and oxygen depletion.
White Cloud Mountain Minnow
Closely related to zebra danios, these minnows originate from cool mountain streams in China. They are hardy fish that can tolerate cold water temperatures. Like danios, white clouds can rely on cutaneous breathing and require little oxygen. They are lively fish that should be kept in schools of 6 or more. A 10 gallon filtered tank is sufficient for white clouds to thrive without an air pump.
Aquarium snails like nerites, ramshorns, and trumpet snails can all survive and breed in low oxygen environments. Their slow metabolism does not demand high levels of dissolved oxygen. Overcrowded snail populations sometimes indicate insufficient oxygenation and water circulation in a tank. But these little clean up crew members will thrive in even unfiltered betta bowls and vases.
African Dwarf Frog
These tiny fully aquatic frogs grow under 2 inches long. Due to their small size, they have a low oxygen demand. Dwarf frogs do well in filtered 5-10 gallon tanks without an air pump. They will occasionally need to come up for gulps of air. Avoid overcrowding and provide ample hiding spots for these peaceful frogs.
Also known as cory cats, these bottom dwelling fish are popular tankmates for bettas and small community tanks. They breathe air through an intestinal modification, allowing them to survive at lower oxygen levels than most fish. However, pools of trapped gas can still accumulate and harm them without water circulation. So a filtered tank is recommended, even without an air pump. Give them plenty of hiding spots and sandy substrate to sift through.
Setting Up a Tank Without an Air Pump
If you want to keep fish that can thrive without an air pump, here are some general guidelines for setting up the tank:
- Tank Size – For fish like bettas, dwarf gouramis, and paradise fish, opt for at least a 5 gallon tank, though larger is always better. Bigger fish like goldfish and larger gouramis need 10+ gallon tanks.
- Filtration – A quality hang-on-back or canister filter is recommended for water circulation and waste removal. Internal filters or sponge filters can work for nano tanks under 5 gallons.
- Substrate – Sand or very fine gravel helps prevent gas bubble buildup. Avoid large gravel and rocky décor that can trap pockets of gas.
- Plants – Include several live plants like anubias, java fern, amazon sword, etc. The plants generate oxygen through photosynthesis to help compensate for lack of aeration.
- Decor – Cave-like décor, rocks, driftwood, etc provides hiding and resting spots for fish. Just be sure decor does not prevent free water flow.
- Stocking – Do not overcrowd the tank, as overstocking increases oxygen demand. Follow general stocking guidelines for the fish species you select.
Signs of Insufficient Oxygen
While the fish described can live without pumped air, it is still important to watch for signs of oxygen deficiency:
- Fish gasping at the surface
- Fish gulping for air more frequently
- Loss of appetite
- Lethargy or hanging at the bottom
- Increased respiration rate
- Sluggish gill movement
- Reduced fin movements
- Low activity levels
If you observe any of these warning signs, take corrective action immediately by:
- Performing a partial water change with properly conditioned water to replenish oxygen levels
- Reducing stocking density if the tank is overcrowded
- Increasing surface agitation and circulation using a filter outlet or air stone
- Adding an air pump to oxygenate the water
- Removing any decor or plants that are blocking surface access
- Eliminating excess waste and uneaten food that can contribute to oxygen depletion
- Testing water parameters to identify any underlying issues with ammonia, nitrites, pH, or temperature that may be contributing to oxygen deficiency
Catching and addressing insufficient oxygen immediately will prevent long-term harm to your fish. Be proactive and observant when maintaining an air pump-free aquarium.
Alternatives to Air Pumps
There are other methods you can use to increase oxygenation in a tank without an air pump:
Aim your filter output at the water’s surface to create rippling. The water movement improves gas exchange. You can also manually agitate the surface with your hand or a designated skimmer tool.
Submersible water pumps and powerheads create directional water flow to circulate and aerate the tank. They are less noisy than air pumps.
Air stones are porous rocks that diffuse air bubbles when connected to an air line. They provide gentle aeration without as much surface disruption as air pumps.
Directing the water flow from internal or hang-on-back filters to create a cascading waterfall effect will improve oxygenation.
Ensure your tank gets adequate lighting to support several live plants. Photosynthesis from the plants releases oxygen into the water.
When to Use an Air Pump
While not mandatory for all tanks, air pumps provide beneficial aeration and circulation. You may want to use an air pump if you have:
- A high stocking level with large or active fish with high oxygen needs
- Goldfish, which produce copious waste that requires strong biological filtration fueled by oxygen
- A heavily planted tank to provide carbon dioxide at night when plants are not photosynthesizing
- Low surface agitation from a low filter outflow or lack of powerheads
- A deep tank over 18 inches where lower levels can become oxygen depleted
So consider adding supplemental air if any of those factors apply to your setup. Air pumps are relatively inexpensive insurance to prevent oxygen issues.
- Many fish like bettas, gouramis, and danios can survive without an air pump due to adaptations that allow them to breathe oxygen directly from the air or through their skin and fins.
- Tanks without air pumps must be monitored carefully to watch for signs of insufficient oxygenation like lethargy or gasping.
- Filtration, live plants, lower stocking, and surface agitation help compensate for lack of an air pump.
- Air pumps are still beneficial for heavily stocked tanks, goldfish tanks, planted tanks, and deep aquariums.
An air pump-free aquarium can maintain healthy oxygen levels with the right fish selection, tank setup, and care routine. Observing your fish and making adjustments as needed is key to success!