Are there any fish that don’t need a filter? The short answer is: Yes!
Some fish that don’t need a filter include Bettas, Guppies, White Cloud Minnows, Zebrafish, and much more. But as a responsible fishkeeper, you’ll want to read this post to learn more about how to add oxygen to a fishbowl or tank.
Here are the 5 main guidelines to follow when choosing a fish species that don’t need a filter:
- Small fish that don’t need lots of open space for swimming;
- Solitary fish that typically don’t do well in community tanks;
- Coldwater fish so they can withstand the often shifts in temperature after water changes;
- Hardy fish that do well even when water parameters fluctuate frequently;
- Avoid overcrowding as a small tank without a filtration system can feel smaller if overcrowded.
But to remove any guesswork, this post will go over the details of some of the best fish that don’t require a filter.
Top 8 Most Popular Fish That Don’t Need A Filter
Fish that don’t need a filter are not automatically low-maintenance fish, but there are some true beauties that are easy to care for, even in a no-filter fishbowl.
These 8 popular fish species are recommended by aquarists that have gone filter-less with their aquariums and have managed to keep healthy & active fish with just a few adjustments to their tank setup.
We’ll touch on the more specific questions about how fish can live without a filter, and how to add oxygen to a fishbowl a bit later.
First, you should get to know the potential inhabitants of your filterless aquarium.
These quick care guides will help you plan your bowl’s setup and give you a heads up on anything else you should know about the 8 most popular fish that don’t need a filter.
1. Betta Fish (Betta splendens)
| Betta Fish (Betta splendens) | |
| Care level | Medium |
| Size | 3 inches |
| Lifespan | 3 to 5 years |
| pH range | 6.5-7.5 |
| Temperature | 76-81°F |
| Temperament/Behavior | Peaceful with the right tank mates Aggressive with other Betta males May be aggressive with other fish with large fins |
| Alternative names | Siamese Fighting Fish |
- Family
Osphronemidae
- Appearance
Betta fish are famous for their extravagant tails, with intensely pigmented colors that become even brighter and more saturated during mating season.
See just how wide-ranging a betta fish tail’s shape can be.
- Habitat
Bettas originate from the beautiful country of Thailand.
Naturally drawn to shallow low-oxygen water streams and rice paddies, these fish will put on the show of a lifetime in any aquarium.
They need plenty of space to move, and a large water surface area, as they “breathe” by using their labyrinth organ to gulp air at the water’s surface.
- Behavior
Male betta fish are notoriously aggressive towards each other, so you should avoid giving them a reason to follow their territorial instinctive behavior.
They are solitary fish that can entertain themselves with the right aqua-scaping setup in a fishbowl.
- Diet
Bettas are carnivores, so they need a protein-filled diet to thrive.
They typically feed at the water’s surface and will accept meaty freeze-dried or live food.
In their natural habitat, they will munch on insects and their larvae.
- Tank mates
Although female betta fish can live in groups of 5 in some circumstances, a fishbowl should only house one betta.
Two males in the same aquarium are a “hard no” in any setup, as they will fight to the death.
| Ideal Tank Mates | Not recommended |
| Mystery Snails | Fish that have large flowing tails |
| Cory Catfish | Oscars |
| Feeder Guppies | Killifish |
| Neon Tetras | Acaras |
| Ghost Shrimp | Parrotfish |
2. Guppy Fish (Poecilia reticulata)
| Guppy Fish (Poecilia reticulata) | |
| Care level | Very easy |
| Size | 0.6-2.4 inches |
| Lifespan | Up to 2 years |
| pH range | 5.5-8.5 |
| Temperature | 75-82°F |
| Temperament/Behavior | Peaceful |
| Alternative names | Million Fish Rainbow Fish |
- Family
Poeciliidae
- Appearance
Also known as “the rainbow fish”, guppies come in a wide range of dazzling colors.
Their coloration and naturally active behavior make them perfect for a fishbowl.
- Habitat
Native to South America, the guppy fish is a freshwater tropical fish that will appreciate a heavily planted aquarium with live rock and a generous layer of substrate.
- Behavior
Guppy fish are active swimmers that enjoy the company of other guppies, as they find safety in numbers.
You’ll notice males doing a fin-wiggle dance trying to impress females when attempting to breed.
- Diet
Considered one of the easiest fish to feed, the guppy is an omnivore that will gladly chow down on live or frozen meaty food (shrimp, bloodworm), peas, cucumbers, and high-quality fish flakes.
- Tank mates
Guppy fish do well with most peaceful community fish, but in a fishbowl, your best bet for the perfect guppy tank mates are more guppies.
| Ideal Tank Mates | Not recommended |
| Mollies | Red-tailed black sharks |
| Ghost Shrimp | Barbs |
| Platies | Tetras |
| Corydoras | Larger aggressive species |
| Gouramis |
3. White Cloud Mountain Minnow (Tanichthys albonubes)
| White Cloud Mountain Minnow (Tanichthys albonubes) | |
| Care level | Easy |
| Size | 1.5 inches |
| Lifespan | 5 to 7 years |
| pH range | 6.0-8.0 |
| Temperature | 64-72°F |
| Temperament/Behavior | Peaceful |
- Family
Cyprinidae
- Appearance
The metallic body and red tail of the white cloud mountain minnow are its most distinctive physical traits, often being mistaken for neon tetras.
Their scales have an iridescent pinkish look, contoured by black lateral stripes.
- Habitat
White cloud mountain minnows are native to the Pearl River of China, with breeding commonly taking place in rice fields.
They’ve also been known to swim along mountain streams, which makes them one of the most robust fish species that you can keep in a fishbowl.
- Behavior
Mountain minnows have a strong schooling instinct, doing best in groups of at least 5 individuals.
They are shy and peaceful under normal circumstances but can show signs of aggression while mating.
- Diet
Natural omnivores, mountain minnows are considered micro-predators.
They will happily feed on zooplankton, algae, micro-worms, and mosquito larvae.
For a varied diet, introduce them to frozen food, fresh fruit, alginate tablets, and dried pellets.
- Tank mates
As they are a peaceful bunch, these minnows can share a tank with most aquarium fish.
| Ideal Tank Mates | Not Recommended |
| Zebra Danios | Tiger Barb |
| Water Loaches | Clown Loach |
| Black Skirt Tetras | Killifish |
| Snails & Shrimp | |
| Dwarf Gouramis |
4. Zebrafish (Danio rerio)
| Zebrafish (Danio rerio) | |
| Care level | Easy |
| Size | 2 inches |
| Lifespan | Up to 5 years |
| pH range | 6.5-7.0 |
| Temperature | 64-74°F |
| Temperament/Behavior | Peaceful |
| Alternative names | Zebra Danio Fish |
- Family
Cyprinidae
- Appearance
The blue/purplish horizontal stripes that run along its body give the zebrafish an easily recognizable look.
It is a slim swimmer that seems almost torpedo-shaped, looking like a silver bullet when zooming around in a fishbowl.
- Habitat
Zebrafish are known to swim in a wide range of waters, considered to be native to India.
They can withstand the rapid waters of fast-moving streams but can also thrive in almost stagnant waters.
- Behavior
With a strong schooling instinct, the zebrafish form a hierarchy whenever they are kept in groups of 5 or more fish.
They are very active swimmers with a peaceful temperament.
You’ll notice them exploring the entire fishbowl.
- Diet
Omnivores by nature, zebrafish are far from being picky eaters.
You can feed them live or frozen invertebrates, and fresh vegetables cut into reasonable pieces.
- Tank mates
Zebrafish are generally considered to be peaceful fish that do well in community tanks, but they may nip at the fins of fish with long and flowy fins.
| Ideal Tank Mates | Not recommended |
| Gouramis | Angelfish |
| Swordtails | Betta Fish |
| Barbs | Guppy Fish |
| Loaches | |
| Corydoras |
5. Dwarf Pufferfish (Carinotetraodon travancoricus)
| Dwarf Pufferfish (Carinotetraodon travancoricus) | |
| Care level | Medium |
| Size | 1.4 inches |
| Lifespan | Up to 4 years |
| pH range | 6.5-8.5 |
| Temperature | 74-82°F |
| Temperament/Behavior | Territorial |
| Alternative names | Pea Puffer Fish |
- Family
Tetraodontidae
- Appearance
A tropical freshwater fish, the dwarf pufferfish is a fascinatingly small yet feisty fish.
You can recognize them by their brightly yellow-colored bellies, and they’re larger than average eyes for a small body.
- Habitat
Native to the rivers, lakes, and estuaries of Southwest India, the dwarf pufferfish will form a strong preference for hanging out in the heavily planted areas of a fishbowl.
In the wild, they will feed, mate, and breed in slow-flowing areas, where plants can keep them sheltered.
- Behavior
These miniature pufferfish are notoriously territorial and aggressive.
They will attack males of the same species but also go after long-finned species in a community tank.
Dwarf pufferfish are a curious bunch, so you’ll find them exploring open areas, as well as finding ideal food scavenging spots.
- Diet
A natural carnivore, the dwarf pufferfish typically lives off of insects, their larvae, algae, and copepods.
You can feed them algae wafers, small shrimp, snails, bloodworms, or brine shrimp.
- Tank mates
A dwarf pufferfish is an excellent choice for a fishbowl, as they do best when living as a single species.
| Ideal Tank Mates | Not recommended |
| Mosquito Rasboras | Large catfish species |
| Ember Tetras | Long-finned Guppy fish |
| Leopard Danios | |
| Neon Tetras | |
| Filament Barbs |
6. Pygmy Corydoras (Corydoras pygmaeus)
| Pygmy Corydoras (Corydoras pygmaeus) | |
| Care level | Easy |
| Size | 1.2 inches |
| Lifespan | Up to 3 years |
| pH range | 6.4-7.4 |
| Temperature | 72-79°F |
| Temperament/Behavior | Peaceful |
| Alternative names | Pygmy Catfish |
- Family
Callichthyidae
- Appearance
Pygmy corydoras, also known as pygmy catfish, are one of the smallest fish species you can keep in a fishbowl.
Their almost adorable aesthetic makes it sometimes hard to distinguish their coloration, as they often grow to be at most 1 inch long.
- Habitat
Pygmy catfish can be found hiding in the riverbeds of the Madeira River in Brazil, the Nanay River in Peru, and the Aguarico River in Ecuador.
They spend most of their lives exploring heavily planted areas.
- Behavior
Typically a bottom dweller, the pygmy catfish will sometimes rise up to the surface of a fishbowl to use their intestine to gulp oxygen from the air when a tank’s water becomes poorly oxygenated.
Temperament-wise, they make peaceful companions even in community tanks.
- Diet
Pellets, bloodworms, brine shrimp, and insect larvae will keep this omnivore well-fed in captivity.
Food that sinks quickly to the bottom of a fishbowl is ideal, as that’s where pygmy catfish will scavenge for food.
- Tank mates
They are best paired with other small peaceful fish, especially with species that hang out in the middle and upper parts of the aquarium.
| Ideal Tank Mates | Not recommended |
| Zebrafish | Any fish that have mouths larger than an inch. |
| Dwarf Gouramis | |
| Cherry Barbs | |
| Neon Tetras | |
| Mollies |
7. Sparkling Gourami Fish (Trichopsis pumila)
| Sparkling Gourami Fish (Trichopsis pumila) | |
| Care level | Easy |
| Size | 1.5 inches |
| Lifespan | 4 to 5 years |
| pH range | 6.0-7.0 |
| Temperature | 76-82°F |
| Temperament/Behavior | Peaceful |
- Family
Osphronemidae
- Appearance
Sparkling gourami fish resemble shiny bullets darting through the water when exploring an aquarium.
With long and thin bodies, they are strikingly colored miniature fish, perfect for a fishbowl setup.
- Habitat
Stagnant waters with heavy vegetation are a sparkling gourami’s safe place in the wild!
They are considered to be native to Southeast Asia and have a reputation of being hardy fish that do well in most captive habitats, including fishbowls.
- Behavior
Sparkling gourami fish will take a strong liking to the planted areas of a fishbowl.
Just like in their natural habitat, gouramis will feel more confident to explore open waters if they have plenty of vegetation to use as a shelter when need be.
- Diet
In their natural habitat, a sparkling gouramis’ diet consists of insects and zooplankton.
These very active omnivores need a protein-rich diet, which you can enrich with artemia flakes, bloodworms, and live daphnia, with some veggie flakes thrown in for variety’s sake.
- Tank mates
Choose peaceful and similarly sized tank mates for your sparkling gourami fish.
| Ideal Tank Mates | Not recommended |
| Neon Tetras | Male Betta Fish |
| Dwarf Pencilfish | Tiger Barbs |
| Dwarf Gouramis | Black Tetras |
| Dwarf Rasboras | |
| Dwarf Suckers |
8. Ember Tetra Fish (Hyphessobrycon amandae)
| Ember Tetra Fish (Hyphessobrycon amandae) | |
| Care level | Easy |
| Size | 1 inch |
| Lifespan | 2 to 4 years |
| pH range | 5.0-7.0 |
| Temperature | 73-84°F |
| Temperament/Behavior | Peaceful |
- Family
Characidae
- Appearance
Pigmented and brightly red/orange colored, ember tetra fish are quite a view when swimming as a school in a fishbowl.
Their coloration has a gradient pattern, which is hard to distinguish, as they grow to a maximum length of about 0.8 inches.
- Habitat
The heavy vegetation and slow-moving waters of the Araguaia River basin are the home of the ember tetra fish in the wild.
A robust and hardy fish that’s resilient enough to thrive even with frequent changes in water conditions!
- Behavior
Ember tetras need a balanced mix of planted areas to hide into and plenty of open space for swimming.
This is an active fish that keeps to its own and has a peaceful temperament even in community tanks.
- Diet
You can feed ember tetras a variety of food, ranging from standard frozen or freeze-dried fish food to live daphnias and brine shrimp.
They may nibble on plants from time to time, but not enough to cause any damage.
- Tank mates
If feasible for your fishbowl setup, the perfect tank mates for an ember tetra are 9 other ember tetras, as they feel best when in large groups.
| Ideal Tank Mates | Not recommended |
| Neon Tetras | Any larger aggressive fish |
| Small Rasboras | |
| Pygmy Catfish | |
| Red Cherry Shrimp | |
| Dwarf Gouramis |
How To Care For Fish That Don’t Need A Filter
Choose hardy cold-water fish.
The water parameters in your fishbowl/ filter-less tank will change very often.
An unfiltered aquarium needs hardy fish as its inhabitants; otherwise, you can end up with a lot of casualties.
Cold-water fish are a good choice because it will be hard for you to stabilize the temperature inside the tank after each water change.
Fish that can sustain lower temperature water will do just fine with up to a 50% water change.
Pick the right fishbowl design.
The main priority when setting up an unfiltered tank is to set yourself up for success.
And success, in this case, is providing as much oxygen as possible without further crowding the bowl.
Choosing an aquarium design that allows for a large water surface area to be in direct contact with the air is ideal.
The larger the area of contact between water and air, the more oxygen your tank will get, and the more carbon dioxide will escape.
Plan for frequent water changes.
Choosing smaller fish and a reasonably-sized aquarium will make this task a lot more manageable.
You should schedule partial water changes once every 3 to 5 days in order to make sure that your fish live a healthy and happy life in your unfiltered tank.
Fish can live without a filter, but they certainly can’t survive in murky oxygen-deprived water.
A 30 to 50% water change will do the trick, although it might sound like quite a hassle.
Consider using a water conditioner when topping off your fishbowl with tap water.
This extra step will neutralize the chlorine, chloramine, and other not fish-safe substances found in tap water.
Add oxygen to your aquarium by setting-up a heavily planted tank.
The natural cycle in a planted fishbowl goes something like this:
- Fish produce nitrogen-rich waste;
- Plants use nitrogenous matter to grow;
- Plants release oxygen into the water while removing carbon dioxide;
- Fish use plants as a food source or as a habitat-enriching element (hiding spots, a refuge during sleep).
If you avoid overcrowding by keeping just a few fish in a tank without a filter, a heavily planted setup will provide more than enough oxygen for your fish to thrive.
Here’s a list of aquatic plants that can work wonders in oxygenating an unfiltered fishbowl:
| Sagittaria subulata | Sunset Hygro | Java Moss | Vallisneria |
| Anubias | Coontail | Rotala rotundifolia | Java Fern |
| Moneywort | Green Hygrophila | Aldrovanda vesiculosa | Rotala indica |
Start off with a well-established substrate base.
A tank’s filter does more than just filtrate water; it also serves as a breeding ground for beneficial bacteria.
You can replicate this “bacterial breeding ground” by planting your aquatic plants in a layer of substrate and letting the fishbowl cycle through this necessary bacterial growth.
Following this process, and adding your fish to the unfiltered bowl only after having a well-established substrate, will allow the plants (with the help of bacteria) to convert fish waste into nutrients.
Consider an alternative sponge filter.
If your only reason for going without a filter for your tank is the bulkiness of it, you should consider substituting it with a sponge filter.
The sponge filter mimics the typical tank filter, circulating water, oxygenating it, allowing good bacteria to develop, and balancing nitrate levels in your fishbowl.
Practice basic aquarium hygiene.
You should, of course, still follow the basic cleaning routine of a filtered tank, paying extra attention to clean the substrate and siphon debris in less-accessible areas of the fishbowl.
FAQs About Fish That Don’t Need A Filter
How Long Can Fish Survive Without A Filter?
Fish can typically survive without a filter for up to 48 hours, depending on the size of the tank and the number of fish.
However, it is crucial to maintain proper oxygen levels and perform regular water changes to ensure their well-being.
What Fish Can Live In A Bowl Without Oxygen Or A Filter?
Although no fish can survive without oxygen, some hardy species like bettas can tolerate low oxygen levels.
However, it is important to note that all fish require oxygen to live, even those adapted to low-oxygen environments.
Proper aeration is crucial for maintaining a healthy and thriving fish in a bowl.
What Fish Don’t Need A Filter Or Heater?
Some fish species that don’t require a filter or heater are bettas, guppies, and white cloud mountain minnows.
These hardy freshwater fish can tolerate a wider range of water conditions than other species, making them suitable for beginners or low-maintenance tanks.
However, it’s important to note that while filters and heaters may not be necessary, regular water changes and proper tank maintenance are still essential for their well-being.
What Are The Best Fish For Bowl Without A Filter?
The best fish for a bowl without a filter include betta fish, guppies, pygmy corydoras, and ember tetras.
These species are well-suited to small aquariums or bowls due to their ability to thrive in limited space and lower oxygen levels.
However, it’s important to provide proper care, regular water changes, and suitable living conditions for their overall well-being.
Conclusion
It is 100% feasible to manage the habitat of fish that don’t need a filter with a few adjustments!
Whether you opt for an unfiltered tank as a challenge for your fishkeeping skills, or as an alternative to the large setup necessary for a filtered tank, you’re in for a treat with any of these 8 resilient fish species.
See a step-by-step aquascaping setup of a fishbowl for a betta fish here:
