[Must Read] Best Fish For a 20-gallon Tank (With Pictures )

[Must Read] Best Fish For a 20-gallon Tank (With Pictures )

Embarking on a journey into the world of aquariums? Explore our guide to discover the best fish for a 20-gallon tank, ensuring a thriving and balanced aquatic ecosystem.

There are a lot of freshwater fish species kept as pets for people across the globe. This type of animal is fairly more economical than other small animals and does not require much maintenance.

A 20-gallon tank is an interesting aquarium size for a novice hobbyist and the more experienced ones. It provides an excellent volume for the care of several species besides occupying little space.

Factors That Influence How Many Fish You Can Keep In 20 days.

The idea of 1 inch of fish per gallon is a bit old and useless. When stocking a 20-gallon tank, you got to be accurate; the tank configuration will influence the number of fish you can keep.

If you want to have multiple species in your aquarium, other factors may come in. A good selection of fish and tank companions is the best choice for any aquarium.

Make sure the animals you are keeping together have the same preference for water conditions.

How many fishes in a 20-gallon tank?

There are various types of species that can be kept in a 20-gallon fish tank. In this article, I’ll present some freshwater fish and stocking ideas for your 20-gallon tank that you can apply or customize for your setup.

How many fish can be in a 20-gallon fish tank?

A 20-gallon fish tank has a lovely size for keeping some fish but stay away from overpopulating it. Too many fish will cause stress and water deterioration, resulting in sick, strained fish.

How many fish can you keep in a 20-gallon tank?

You should be able to fit around 15-20 small fish for a 20-gallon tank. A goldfish can overgrow, so these kinds of fish are not for this size of the tank.

How many fish can a 20-gallon tank hold?

Usually, people think of a certain number if they’re tempted to keep a certain quantity of fish from their tank. Instead, make sure to spend time researching the fish you plan to keep.

Learn their needs and temperament and try to figure out how they fit together with tank mates. This is especially important when you’re trying to select the right fish for 20-gallon tanks.

During your research, you will also need to consider the different parts of your tank. Some fish occupy the upper part of the water column, some in the center and others in the bottom.

How many fish for a 20-gallon aquarium, stocking ideas

A container of 20-gallon water has 20 1-inch fish per gallon of water. Remind yourself that the length of fish described in this article will be the maximum length you can comfortably keep in a 20-gallon tank with the best environment and the proper maintenance.

Big fish for your 20-gallon tank

If you have a big fish in your tank, I suggest thinking about buying a larger tank. Those are fish which you should avoid.

Best fish for stocking a 20-gallon tank – ideas & combinations

A 20-gallon tank is a mid-size tank, so you’d want to be careful what fish you fish and what type to keep. The best fish we have found for a 20-gallon aquarium is the fish you can keep in small low-tech tanks.

Which fish is best for a 20-gallon tank, and how many can you fit

A 20-gallon tank is ideal for a beginning enthusiast because it offers plenty of options of fish to choose from. You can keep all sorts of aquatic fish and plants. We give you some of the most excellent fish you can keep in your 20-gallon tank in this guide.

Guidelines for stocking your 20-gallon tank

However, in some aquariums, owners overstock their tanks often. It can be considered certain factors for measuring safe stocking levels.


Generally speaking, your guideline for stocking your aquariums is about its filtration system and common sense about physical space for fauna to swim, hide and have a peaceful corner in the aquarium. For this, perform tests to assess the aquarium’s water quality, know the efficiency of filtration, and find out if your aquarium is full of fish.

Stocking your freshwater aquarium

A 20-gallon aquarium allows you to keep many live plants and various beautiful freshwater fish, and exciting animals. I listed some of the most fantastic fish for a 20-gallon tropical tank. Every fish, critter, plant, and decoration in a tank play a role in the health of the aquarium. The goal of making these micro-ecosystems is to build one that requires as little effort as possible to keep going.


Livebearers are freshwater creatures who give birth to tiny fry. These fishes may be the most commonly encountered within an aquarium, with most coming from the family Poeciliidae.

It includes guppies, mollies, swordtail, platys, and others. One benefit of keeping livebearers is that they’re easily bred. There are many species where the males fight each other when trying to mate.


Bettas are slow-swimming fish. They most often swim on the top of the tank. Shrimp can also live with betta fish, but you have to provide them with hiding places not to become a meal for the fish.

Siamese Fighting Fish can thrive in a 20-gallon aquarium. Choose peaceful but quick-moving fish for tank partners; avoid fin nippers.


Neon tetra fish are most widely used for aquarium fishing. Tetras generally have tiny, compressed, and brightly colored bodies. Other than Neon Tetra, Black Neon Tetra can also do well in 20-gallon tanks.

They’re easy to rear. It’s best to keep them in schools of at least six fish. Other tetra species include the Rummynose Tetra, the Black Phantom Tetra, and the Glowing Light Tetra. Tetras can make an essential part of the aquarium.


You can keep dwarf cichlids in a 20-gallon tank. Angelfish, Discus, and other cichlid grow pretty massive and rapidly to be held in a 20-gallon tank. Dwarves can get territorial during the breeding process. It is not uncommon to keep Rams and Apistos in these sizes of tanks.

Dwarf Gourami

Dwarf gouramis are the only fish in this list I’d consider semi-aggressive. In general, they are mostly peaceful and can offer superb communities fishing.

If there are two, they can fight, or you may bully either partner. To reduce the chance that this happens, try to avoid using two males in the same tank. It is also a good idea to provide an area in your aquarium so that a bullied animal can hide.

Can you list the best fish combinations for a 20-gallon tank?

In general, when filling your 20-gallon tank, try to have one or two bigger “centerpiece” fish and fill the rest with a class of smaller fish and a few bottom dwellers like snail or shrimp.

In general, twenty-gallon tanks should be a perfect size for a novice tank owner. And always remember that it’s crucial to understand the nitrogen cycle and how to maintain healthy water conditions for your fish.


Zebra Danios are exceptionally active fish that generally stay in the upper areas of an aquarium. They are native to South Asia and rely on a large tank because they love swimming and chasing other fish.

Other Danios can be kept in 20 gallons of tanks, including Danio Marginatus, Pearl Danio, and Celestial Pearl Danio. These fish can also fight with other fish, such as guppies and others, so be aware when stocking up your aquarium. The danios zebras are happier in groups with five to six fish.

Best fish for a 20-gallon tank


Swordtail’s appearance is almost the same as those of platies. In an aquarium situation, you need a male for every two females. It reduces the stress on the female when the males start harassing them.

Best fish for a 20-gallon tank


Aquarium shrimp can add a fun element to your aquarium as they come in multiple sizes and colors. They also molt as they grow that inevitably makes them shed exoskeletons. They are scavengers who eat anything, including animals and plants (dead or alive).

Best fish for a 20-gallon tank


Otos are cute little shoaling fish that go into glasses into a 20-gallon tank. They are little plecos that remain small, and you can keep a small group in a tiny tank. You might want to enhance his diet with algae wafers. The fish are the best algae eaters for small tanks.

Best fish for a 20-gallon tank


Barbs usually live in schools in soft, acidic water. Most barbs are fin nibblers and don’t like long-finned fish. Barbs can even kill other fish. They are a very active type of fish.

Best fish for a 20-gallon tank


Rasboras are possibly the best kind of fish for small community tanks. These fish also originate from freshwater habitats in Southeast and South Asia. Due to their peaceful nature, they are excellent tankmates. Also, these fish shows unique breeding and shoaling habits, all with fantastic color. These examples of common Rasbora species regularly held in aquariums are Red-Lined, Pygmy and Harlequin.

Best fish for a 20-gallon tank


Cory catfish are an excellent addition to any tank. They will eat leftover fish foods that get lost in the tank. They’re big-bodied schooling fish.

Best fish for a 20-gallon tank

Tell me the biggest fish you can put in a 20-g bag?

You want to keep fish less than 6 inches in size. Fish has to have space in the tank to swimming and also relaxing. Avoid keeping large numbers of fish in a small tank.

Additional factors

Any extra addition to the tank will reduce the amount of space that is available to the fish. Plants and gravel could also impede the flow of water in the tank.

Always add filtration and aeration. But you shouldn’t rely too much on such aid, as any blackout will be disastrous; keep an eye open.

Fish You Shouldn’t Keep In A 20-gallon tank.

There is also lots of fish that should never be kept in a 20 gallons tank. It’s not acceptable to fill tanks with large cichlid or other large fish.

Angelfish are territorial species that have a semi-aggressive temperament and can kill smaller fish. In addition, Common plecos grow faster even as juveniles as they can occupy all the tiny tanks in a short time.

Goldfish can die prematurely in small aquariums.

Best live plants for a 20-gallon tank

Planting Vallisneria in your 20-gallon tank is the best way to turn your nano aquarium into an aquatic jungle. Amazon’s Sword is a good option for nano tanks.

Sagittaria dwarf has a grass-like appearance. A lot of Wisteria species can make excellent places of cresting for fish. It flourishes with liquids or tablets of fertilizers and tends to take over the underwater landscape as it can propagate via side shoots. It is easy to take care of.

Size considerations

Many times the fish bought in the pet store are youngsters that will grow more. Check the average size of each fish when mature, and use this measurement to figure how much space the fish need. It’s not unusual for a fish to double in size pretty quickly.

Specific needs

Most fast swimmers need more area than slow swimmers, even though they tend to be active all the time. You’d better give your fish plenty of room to eat, which helps protect the peace by decreasing the number of unpleasant encounters.

Some large fish will produce more waste than much smaller fish and can alter your storage capacity or tank filtering ability as well, when in a 20-gallon tank.

Lights for a 20-gallon tank

Lighting is critical to fish to maintain the day and night cycle. Although there are plenty of lights available, it is better to turn off their tanks at night. Adjust in the minimum of 12 hour light and 12-hour dark.

Fish tank filtering system in a 20-gallon tank

That filter is the critical component in every tank. Filters keep good bacteria and make sure to keep the water free from pollutants for longer. The best the filter system, the healthier the fish, and the less maintenance is needed.

20-gallon tank water heater

A simple water heater offers a better quality of life to the 20-gallon fish tank residents. The heater is essential to keep the temperature stable; the fluctuation of this parameter and others can cause a drop in the fish’s immune system, causing diseases and other pathologies present in the tank to appear. It’s easy to set up a thermometer when looking for a quick and easy way to monitor the temperature.

The last step is adding water.

Once you have assembled the basic structure with the tank, heater, filter, lighting, plants, logs, and other decorations, it’s time to fill it with water.

Depending on the substrate you use, the water can get murky the first time you fill the tank, and you might have to wait for patience till the debris settles in.

If you add some fish to your new tank – without cycling it – you’ll have to perform numerous water changes; otherwise, you will have a big ammonia problem. Before adding fish, keep your tank going (while full of water) for 2 to 4 weeks for the bacteria to attach themselves to your filter so that they can carry out the nitrogen cycle and be able to maintain a good quality of water in your aquarium.

Good luck with your aquarium!

A 20-gallon aquarium includes stocking options outside of its 10,000-gallon capacity. If you want big fish or many fish, you will probably be better off getting a 55-gallon tank or bigger.

Or if you’re going to set up a small community with some beautiful fish and maybe some excellent plant, having one this size will probably suffice. This article is not meant to supplement diagnosis, prognosis, treatment, prescription, or a qualified veterinarian’s formal guidance.

Final thoughts

A 20-gallon tank is a perfect aquarium for any beginner. It provides a chance to care for different animals without taking too much space. Always ensure to keep track of the size of the fish species when stocking.

In any case, ensure it is the right environment for the species of your choice. Set up and decorate the aquarium correctly with a heater, filter, plants, and everything else you want.

Remember to make space available for the animals to swim, hide and rest whenever they want. Use common sense when populating the tank, and know the habits of the fish you want to keep; this will help you choose which area of the aquarium to occupy.

Keep your maintenance routine up to date, keeping your water always in perfect condition; that way, you shouldn’t have any problems.

{Updated 2022} Top 10 Best Aquarium Starter Kits For Beginners

{Updated 2022} Top 10 Best Aquarium Starter Kits For Beginners

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Keeping an aquarium is a great hobby, but when you’re just starting out, it can be a bit overwhelming. There are some essentials you need to get your tank up and running, but how do you know what works best together?

One of the best places to start is with an aquarium kit. This is generally the most cost-effective way to get all or most of the products you need to get started without having to go to the pet store ten times. But not all aquarium kits are created equal! We’ve put together reviews of our favorite aquarium kits, including our best overall pick, best pick, and best premium kit.

Comparison Table

CustomSiteStripe ImageTitleReviewBuy
Top Performance Aqueon Fish Aquarium Starter Kits LED NeoGlow4.5/5.0Check Price
cheapestMarina LED Aquarium Kit4.4/5.0Check Price

Fortunately, there are many great starter kits to get you started. The best aquarium starter kits include the tank itself, as well as a suitable filter, multi-stage filter cartridges, water conditioners, and more. You get everything you need to set up your aquarium and get it ready for fishing.

In this guide, you can learn what makes the starter aquarium best for a freshwater community. Find out how to choose the perfect fish to suit your new aquarium and check out our reviews and recommendations for the best beginner tanks on the market today.

The 10 Best Aquarium Starter Kits For Beginners

Best Aquarium Starter Kit Reviews

1. MarineLand Portrait Glass LED Aquarium Kit

best aquarium starter kit

It is a standing glass tank from MarineLand that comes with everything you need to set up your first aquarium. Plus, it’s a beautiful tank that won’t take up too much space on your table or counter. The shape of the portrait is unique and the curved edges give it a sleek and modern look.

A five gallon tank is a great size for beginners and everything you need is included. A three-stage filter with adjustable water flow is hidden in the rear panel. All cables are also concealed and the filter works quietly. Filter cartridges are also included.

This kit includes a hinged light above the tank that uses white and blue LEDs. You can create a suitable day and night cycle: white for bright daylight and blue for soft moonlight. A sliding glass canopy keeps debris out of the water and fish jumping without distracting the style.

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2. Aqueon Fish Aquarium Starter Kits LED NeoGlow

best aquarium starter kit

This Aqueon starter kit is a great way to get started. It’s 10 gallons, so it gives you a little more choice in terms of how many fish you can keep. In addition, the neon silicone edges create a really modern look. Choose from orange, pink and green.

It includes a black background, bright multicolored gravel and three plants so you can settle in right away. The unobtrusive hood keeps the tank from looking too bulky and the integrated blue light makes the neon colors shine.

This kit also includes a silent flow filter, a medium filter cartridge and a water conditioner to start cycling right through the tank. It comes with fish food and a preset warmer, so it’s all set for when you add your fish.

The black gravel, bright colors and blue light create a truly unique look that adds something extra that you don’t get in most aquariums. It will really become an eye-catcher in your home.

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3. Marina LED Aquarium Kit

best aquarium starter kit

If you want a larger aquarium, this marine kit comes with a 20 gallon tank and includes everything you need to get started. With the clip-on filter and the quick-change filter cartridges you can immediately start circulating your water. It even contains conditioned water to make tap water safe for your fish.

An LED lamp is built into the canopy that provides a natural light effect and a simple on/off switch so that you can switch off the light in the evening. You’ll also get a soft mesh net, a biological supplement to encourage the growth of beneficial bacteria, and an aquarium guide to get you started.

This is a simple design with a black cap that helps maintain water temperature and prevents fish from jumping. Since it’s a bigger tank, you also have a lot more options when it comes to what kind of fish you can have in it.

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4. Tetra Crescent Acrylic Aquarium Kit

best aquarium starter kit

This five gallon acrylic tank is a great option for small spaces. Keep it in your office, bedroom or directly on your counter. The seamlessly curved front looks sleek and modern and the black frame and upholstery blend in with any interior.

The included filter uses a double-sided dense mesh cartridge for mechanical filtration and activates charcoal to remove odors and any contaminants to keep the water clear and clean. Also included is a biobag for beneficial bacteria needed to balance water chemistry.

This is a perfect size aquarium for up to three community tropical fish or a single goldfish. Hidden LED lights illuminate the tank without being too obtrusive and the lid is designed for easy cleaning and water maintenance.

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5. Aqueon LED Aquarium Kit

best aquarium starter kit

Another great starter kit is this 15 gallon tank from Aqueon. It comes with all the essentials: a preset heater, thermometer, bell with LED light, a Pro Power filter and a filter cartridge, as well as fish food, a soft mesh net and water conditioner.

The great thing about the filter included in this kit is that it has an LED indicator that lets you know when it’s time to buy a new cartridge. If the light flashes, it’s time for a new one. This helps to maintain a healthy environment for your aquarium by ensuring that the water is as clean as possible.

This tank has a slim design that gives your fish plenty of vertical space to explore. It is an attractive and modern design that will become the center of attention in any room. It doesn’t take up too much space either, so it won’t be difficult to find the perfect spot for it.

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6. Koller Products Panaview Aquarium Kit

best aquarium starter kit

This 5 Gallon Aquarium Kit from Koller Products is a great option if you’re looking for a small, simple tank for your desk or counter. It is made from a single piece of clear plastic and because it has fewer seams than a glass tank, there is less chance of leakage.

LED lighting comes in seven different colors to choose from: white, blue, amber, green, red, purple and aqua. There are also four different lighting patterns to choose from for that transition from one color to another.

This kit includes a powerful internal filter with a flow rate of 45 gallons per hour, keeping the water as clear and clean as possible. The hood is designed to tilt up to allow moisture to drip back into the tank, keeping your table or countertop drip-free while cleaning or feeding.

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7. Tetra 20 Gallon Complete Aquarium Kit

best aquarium starter kit

This all-in-one aquarium kit from Tetra comes with a 20 gallon glass aquarium, LED bell, Whisper 20 filter, Tetra HT 20 heater and several artificial aquarium plants.
Available in four different sizes ranging from 10 gallons to 55 gallons and comes with additional accessories such as a digital thermometer, fishing net, water conditioner, filter media and more.

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8. SeaClear 20-50 Gallon Acrylic Aquarium Kit

best aquarium starter kit

This aquarium kit may not be as complete as some others on the market, it has an acrylic aquarium that is much stronger and more impact resistant than a glass tank.

Available in sizes ranging from 20 gallons to 50 gallons, this kit comes with a 24-inch bulb and reflector, as well as a colored background.

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9. Fluval Edge Aquarium with LED Light

best aquarium starter kit

Uniquely designed to hide tank wiring and equipment, the Fluval Edge Aquarium Kit is a very attractive option.
This kit includes a six-sided glass aquarium for 360-degree viewing, as well as an LED light, a Fluval flow filter, and all the necessary filter media. The tank looks great, runs quietly and is very easy to install and maintain.

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10. GloFish 29236 Aquarium Kit

best aquarium starter kit

The GloFish Aquarium Kit is a good, inexpensive option for smaller fish and invertebrates. The kit comes in 1.5 and 3 gallon options and is made of plastic with a clear plastic fuel cap. The 1.5 gallon tank measures 7.25″ x 8.5″ x 11.5″ and sits on a black pedestal base. The tank is made of seamless plastic and has a solid black bottom.

This kit includes a 2-stage filtration system and an easily accessible hood that opens with a hinge and has built-in LED lighting. Like most GloFish tanks, it features blue LED lighting to bring out the bright colors of GloFish, but will create the same effect with goldfish, guppies, tetras, bettas and other types of colored fish and invertebrates. This lighting effect gives this tank a special interest and makes the tank small enough to sit on a desk, in a hallway or even in a bathroom.

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What is the Best Aquarium Starter Kit?

All these kits are great and they are so different that it is really hard to pick just one, but we really love the Aqueon LED Aquarium Kit.

It comes with a large number of accessories, including a filter cartridge, heater, net, water conditioner and fish food.

The filter has an LED indicator light that lets you know when it’s time for a new filter cartridge, which is a great feature that can have a big effect on your water quality if you don’t always remember when it’s time to change the filter. filter.



There is a lot to consider when choosing a Best aquarium starter kit. Remember that the bigger the tank, the more fish you can have. First, figure out what type of fish you want and which tank size best suits your space and budget.

These kits have everything you need to get your tank up and running and some even come with water conditioners, fish food and other things you need to maintain your tank and keep your fish happy and healthy.