Neon tetras are tiny fish that don’t produce much waste – this begs the question, do neon tetras need a filter? Yes, neon tetras need a filter for their tank. Leftover food, floating particles, and decaying organic matter can build up over time in the aquarium, making living conditions unsafe for your fish; filters remove not only this material but also promote aeration. Aeration is essential as neon tetras would otherwise suffocate.
Why Do Neon Tetras Need A Filter?
Like all fish, neon tetras regularly excrete while swimming in the water. You must remove this waste, otherwise, the waste toxins will become more concentrated over time and poison your fish. The early stages of this poisoning are known as ammonia stress, which can become fatal.
Aside from ammonia poisoning, floating bacterial particles from decaying organic matter can develop into cloudy ammonia water if unchecked. Murky water can make it difficult to see the health condition of your neon tetra.
Filtration is essential to the well-being of your neon tetra; it makes the aquarium look nicer and reduces the care needed to keep happy fish. Unfiltered systems require 80 to 90 % daily water changes, whereas filtered systems only need a 10 to 15 % weekly water change. Filters make life better for your fish and you.
There are three main ways to filter aquarium water: biological, mechanical, and chemical. Biological filtration is essential to any aquarium as it keeps maintenance low. Mechanical filtration helps keep the water clear, while chemical filtration deals with any source water issues; it can also eliminate certain toxins or medication added to the system. Keep in mind that crystal-clear tank water can still be toxic to your fish, while murky water can be perfectly safe.
(For more information on caring for neon tetras check out our article – How To Care For Neon Tetras)

Filtration Methods
1 Biological filtration
The process of biological filtration involves bacteria, plants, fungi, and microorganisms converting your fishes’ waste into not-so-harmful material. When your fish expel waste in their tank water, this waste can become toxic to your fish over time. Your fish’s waste, dying or decaying plant matter, leftover food, and dead fish can turn into toxic ammonia; a biological filter converts this colorless gas into Nitrite and toxic Nitrite to Nitrate. Nitrate might be relatively harmless, but if it’s not removed from the aquarium through frequent water changes, it can cause numerous health problems for your fish. These problems include suppressing your fishes’ appetite and inhibiting their gill’s ability to absorb oxygen from water. Nitrate can also cause algae growth.
Biological filtration occurs during a “cycling” process. Even the best biological filters cannot adequately process fish waste until it has undergone the cycling process. Plants use nitrogenous waste as fertilizer but can only photosynthesize during the day. However, the concentration will be so minimal that it won’t significantly affect the water quality. Plants respire at night and produce nitrogenous waste.
2 Mechanical filtration
Mechanical filtration operates by pushing the water through a filter media that acts as a strainer – this catches free-floating particles unable to pass through media openings. The filter media can be filter floss, sponge, special filter pads, or aquarium gravel. The finer the media, the better it will be at catching smaller particles. However, finer media gets plugged more readily and requires frequent rinsing and replacing. Coarser filters allow more pieces through but take longer to get plugged up. Often mechanical filters use many media layers, beginning with coarse and ending with fine media for optimal water cleaning.
Debris will collect in the water in the time it takes for all the water to go through the filter. Inevitably, the water will become murky as more debris settles in the bottom of the tank.
It is best if you regularly clean out your tank; otherwise, the mechanical filter will become plugged with dirt and debris, and it won’t work as efficiently. Some neon tetras have messy habits like digging and generally being messy eaters – this will contribute to a dirty tank. Overfeeding can be problematic, along with other tank issues, as the mess it leaves behind can weaken the mechanical filter.
3 Chemical filtration
Chemical filtration removes toxins from the water by carbon or chemical resins. Activated charcoal thoroughly extracts chemicals toxins from the water until the carbon gets saturated – you must change activated filter carbon often. Bear in mind that carbon for tank use doesn’t remove ammonia, Nitrates, Nitrites, oxygen, or carbon dioxide. Always review the information on the packaging so that you can use it properly for a specific job.
Usually, just one cubic inch of activated carbon offers chemical filtration for 2 gallons of water for about a month, although certain conditions must be met for this to work:
- The entire tank water needs to move through carbon at least twice an hour. Water flow must move quickly and often to be exposed to the carbon, so it removes chemicals sufficiently.
- Abnormally hard or soft water or water with high mineral concentrations will saturate your carbon more quickly. Adding plant foods or mineral supplements to your water will saturate the carbon faster as it works even harder to remove chemicals from your water.
- You must change your water frequently to prevent chemical buildups in the water, which only makes it more difficult for your chemical filtration to work.
- Be mindful not to overpopulate your tank as it puts a lot of pressure on your chemical filter or any filtration system, for that matter.

Types Of Tank Filters
1 Submersible aquarium filter
The submersible aquarium filter is the most common one; it has a powerhead that effectively aerates the water. These filters have suction cups that you can attach to the aquarium glass.
2 Hang-on filter
The hang-on filter requires replaceable cartridges, although good quality ones offer three types of filtration. They create small waterfalls that provide necessary aeration to the water.
3 Canister filter
The canisters are the best quality and most expensive filters on the market. They function using the three filtration methods, and you can add, change, or remove filtration material as needed. Canisters maintain the cleanliness of water for a longer time in comparison to the other filters.
Canister filters are the best choice for larger aquariums as they provide vast water flow with their powerful filters.
What Would Happen To My Neon Tetra Without A Filter?
Some neon tetra owners choose not to outfit their tank with a filter instead, using plants to deal with the bioload from their fish. If you decide to use plants solely in your aquarium, you must know what you are doing. An unfiltered tank can be a unique challenge but one that requires a lot of research to continue maintaining high water quality.
Suppose there is weak or no filtration whatsoever in the aquarium. In that case, the decaying organic matter can become highly toxic and cause ammonia stress, resulting in ammonia poisoning, and becoming fatal. Aside from that, you don’t want your neon tetra swimming in dirty, cloudy water, it looks terrible, and you can’t see your beautiful fish.
Neon tetras need lots of oxygen, and filters are best for providing oxygenation and aeration. Filters aid water circulation by encouraging the water from the tank’s bottom to come up to the top to absorb oxygen. Without oxygen, neon tetra would suffocate. Be sure to provide your tank with a powerful model for optimum aeration.
A lack of filtration can also contribute to neon tetra disease. Neon tetra disease can occur in other fish but mainly neon tetras. The organism Pleistophora hyphessobryconis causes the disease, and there is no known cure other than to remove the infected fish from the remainder of the aquarium.
Neon tetra disease occurs when fish consume live food servings or the particles of their deceased tank mates. Parasitic spores enter the healthy fish’s body and begin consuming the host. Cysts will appear in the infected host as they deteriorate from the inside out.
As previously mentioned, no cure or treatment exists for this disease other than to remove the infected fish and euthanize it to avoid further contamination. It can easily be prevented by maintaining high-quality water levels – this includes regular cleaning and excellent filtration.

In Conclusion
Neon tetras are no different from other fish; they need sufficient oxygen to live. Filters not only help to eliminate toxic substances in your tank, but they also stir the water, thus promoting aeration. With a decent filter, you won’t need other aeration devices. The most important factor to consider when buying a filtration system for your tank is to consider its size and your fish’s specific needs.
As necessary as proper filtration is to the health of your neon tetra, you must still keep up with your tank’s maintenance, as it is easy to evade this responsibility. Along with decent filtration, your fish need tank cleaning, water changes, and frequent inspection for disease, stress, conflict, hunger, or any other issues.
Many different types of filters include submersible and non-submersible. Choose a filter that meets your fishes’ needs.