15 Beautiful Fish For A 15 Gallon Tank! (With Pictures)

A 15-gallon tank presents a wonderful opportunity for aquarium enthusiasts to create a beautiful aquatic environment for a variety of small fish species. Although small, you can create a thriving nano community tank of fish or keep a small number of larger fish in the tank without issue.

To ensure the health and well-being of your fish, it is crucial to select the appropriate species that will comfortably coexist within the limited space of the 15-gallon tank.

Some great options for stocking a 15-gallon aquarium include danios, guppies, tetras, platies, corydoras catfish, and dwarf gouramis. These fish species are not only attractive but are also peaceful and hardy, making them perfect for beginners and experienced fish keepers alike.

When introducing new fish to your tank, be sure to carefully research their specific needs, including diet, water parameters, and compatibility with other species. Creating a harmonious and stress-free environment for your fish will encourage their natural behavior and allow them to thrive in your 15-gallon tank.

Getting The Most Out Of Your 15 Gallon Aquarium

Harlequin Rasbora
Harlequin Rasboras

A 15-gallon aquarium provides a decent amount of space for a nano tank that allows you to keep various fish and aquatic creatures to thrive in a home or office setting. There are several types of 15-gallon tanks, with tall, long, cube, and bowl designs being available.

All can work well, but depending on the needs of the aquatic life, some might be more suitable than others. In this section, we will discuss how to make the most out of your 15-gallon tank.

If possible, we would highly recommend that you go with a long tank design if possible. It provides ample horizontal swimming space for fish that prefer to swim longer distances such as tetras and rasboras that are perfect for smaller tanks.

This type of tank also allows for better water circulation, as well as offering sufficient space for appealing aquascape designs. Additionally, a long tank can accommodate a larger variety of fish species given its horizontal orientation.

Cardinal Tetras

When stocking a 15-gallon tank, it’s crucial to choose fish that are small in size and won’t grow too large. This is especially true for those who opt for a tall or cube design, as they might have more vertical space, but aren’t as ideal for fish requiring lateral swimming room.

It’s essential to provide proper filtration and water movement in smaller tanks so we highly recommend that you use a filter. Ensuring that your tank is equipped with an efficient yet quiet filter will contribute to a healthy environment for the fish and help keep the tank looking clean and clear. Additionally, consider adding a small heater if appropriate for your choice of aquatic life, and a thermometer to monitor water temperature.

A Female Betta Fish

A Betta Fish
A Betta Fish

A female betta fish can be an excellent centerpiece fish for a 15-gallon tank. Technically, you can keep two female bettas in a 15 gallon tank if the setup is perfect but we wouldn’t recommend it for beginners.

They showcase vibrant colors and elegant fins similar to their male counterparts but often exhibit lower levels of aggression. This makes them more suitable for community tanks and allows for the addition of tank mates to occupy the remaining space in the tank such as keeping ember tetras with your betta.

As we mentioned in our article going over betta tank sizes, when setting up a 15-gallon tank, it is crucial to maintain proper water parameters, suitable for the betta as well as their tank mates. Betta fish are native to Southeast Asia, where they inhabit shallow freshwater environments like swamps, marshes, and rice paddies.

These environments are characterized by warm temperatures so we recommend you aim for the following water parameters in your tank:

Water Temperature: 78-80F
Water Flow: Still-Low
pH: 6.8-7.5
GH: 3-4 dGH
KH: 3-5 dKH
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: <20 ppm

Introducing compatible tank mates alongside the female betta not only helps diversify the aquatic ecosystem but can also encourage natural behavior among the fish. A number of the other fish featured in this article can work well as a tank mate for your betta.

As with any fish species, it is essential to keep the tank clean and well-maintained. Regular partial water changes should be performed, and a high-quality filter is recommended to reduce waste buildup. Our betta fish care guide goes into far more detail on this though.

In conclusion, a female betta fish can be an ideal choice for the centerpiece of a 15-gallon tank due to its lower aggression level and compatibility with other tank mates. Ensuring the tank has a proper setup and regular maintenance will enable the healthy coexistence of various species and create an enjoyable aquatic environment for both the fish and their owner.

An infographic going over a BETTA FISH CARE sheet

Dwarf Gourami

fish for a 15 gallon tank
A Dwarf Gourami

Dwarf Gourami, scientifically known as Trichogaster Ialius, is a colorful and attractive freshwater fish that belongs to the Gourami family. They are a popular choice for aquarium enthusiasts due to their vibrant colors and relatively easy care requirements.

It is possible to house 2-4 Dwarf Gourami in most 15 gallon tank designs. However, it is usually recommended that keep this type of tank as a species-only tank due to some Dwarf Gourami exhibiting aggression towards their tank mates.

Female dwarf Gourami are generally shy and easygoing, but they can become territorial in smaller spaces. Providing ample hiding spots, such as plants and small caves, can help reduce stress and aggression in a 15-gallon tank.

A Dwarf Gourami
A Dwarf Gourami

It is essential to maintain clean water and regular water changes for optimal health and well-being of these fish. We recommend the following water parameters for dwarf gourami:

Water Temperature: 72 – 82°F (22 – 27°C)
Water Flow: Still-Low
pH: 6-7
GH: 3-10 dGH
KH: 4-8 dKH
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: <10 ppm

When considering tank mates for Dwarf Gourami, it is crucial to ensure that they are compatible in terms of water parameters and temperament. Some well-suited tank mates include Guppies, Mollies, Platies, Swordtails, Neon Tetra, Chili Rasboras, Zebra Danios, and Cory Catfish.

However, due to the potential for aggression in a 15-gallon tank, it is advisable to keep Dwarf Gourami as a single species in the tank.

In terms of diet, Dwarf Gourami are omnivores and can be fed a variety of food options such as flakes, pellets, and freeze-dried or frozen food. Supplementing their diet with live or frozen brine shrimp, daphnia, and bloodworms can add necessary nutrients and variety.

In conclusion, while a 15-gallon tank can house 2-4 Dwarf Gourami, it is vital to understand the risks of aggression and territorial behavior in a smaller setup and select the appropriate tank mates if needed. By providing proper care and an appropriate environment, Dwarf Gourami can thrive and bring colorful, engaging visual appeal to any aquarium.

Honey Gourami

A Honey Gourami
A Honey Gourami

Honey Gouramis (Trichogaster chuna) are beautiful and peaceful freshwater fish that can thrive in a 15-gallon tank. These fish are less aggressive than their dwarf gourami cousins, making them an excellent centerpiece fish in a community tank. If you prefer, you can choose to keep 1 or 2 honey gouramis as the main attraction in your 15 gallon tank with a number of tank mates.

These fish are not only visually appealing but also relatively easy to care for, making them ideal for beginners and experienced aquarists alike. They are widely available in most aquarium pet shops and are generally quite affordable making them a great beginner-friendly fish.

As we covered in our article on keeping betta fish and gourami in the same tank, you can technically keep a honey gourami and betta in a 15 gallon tank but this will be challenging and not recommended for beginners.

A Honey Gourami Fish
A Honey Gourami

An alternative option for those who love Honey Gouramis is to create a species-specific tank. In such a setup, you can house 4 or 6 of these fish comfortably in a 15-gallon tank. If you are a beginner, we would usually recommend that you stick to all females but keeping the tank planted can help reduce any potential problems with aggression from males.

When considering tankmates, there are a variety of species that can coexist peacefully with Honey Gouramis. Some popular options include small schooling fish such as tetras, rasboras, or corydoras catfish. These community fish will add some variety to your aquarium without causing any harm to your Honey Gouramis.

We recommend the following water parameters for honey gourami:

Water Temperature: 74–82°F (23–28°C)
Water Flow: Low
pH: 6.0-8.0
GH: 6-12 dGH
KH: 3-8dKH
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: <10 ppm

In conclusion, Honey Gouramis are a versatile and beautiful addition to a 15-gallon tank. Whether you choose to keep them as centerpiece fish or in a species-specific tank, they will undoubtedly bring a sense of tranquility and grace to your aquarium.

Tetras

Cardinal Tetras
Cardinal Tetras

Most types of tetra can work well in a 15 gallon tank which makes them a popular choice for small community aquariums. The number of tetras can be adjusted as required, with 6-8 being a great number for a small school as a secondary feature to a centerpiece fish.

Here are the recommended stocking numbers for the most popular types of tetra for a 15 gallon tank:

  • 6-20 Black Neon Tetras: These tetras are known for their attractive black and neon blue horizontal stripe, making them visually striking in an aquarium setting.
  • 6-14 Black Skirt Tetras: With a predominantly black body and silver vertical stripes, black skirt tetras bring a unique appearance to the tank.
  • 6-12 Bloodfin Tetras: Their notable red-finned appearance adds a touch of bright color to the aquarium.
  • 6-15 Cardinal Tetras: These tetras have a stunning combination of red and neon blue stripes, making them a popular choice among hobbyists.
  • 6-30 Ember Tetras: Tiny and vibrant, ember tetras are well suited for nano tanks. Their small size (around 0.8 inches) allows for a larger number in a 15-gallon tank.
  • 6-15 Emperor Tetras: Boasting an iridescent blue/purple coloration, this tetra species reaches up to 1.6 inches and requires a 20-gallon tank.
  • 6-30 Glowlight Tetras: They display a notable orange neon stripe, which appears to glow under aquarium lighting, adding a unique touch to the tank.
  • 6-35 Green Neon Tetras: Similar to neon tetras, these fish have a green hue in their horizontal stripe, making for a distinctive appearance.
  • 6-14 Lemon Tetras: Named for their bright yellow coloration, these tetras bring a splash of color and contrast to the aquarium.
  • 6-20 Neon Tetras: One of the most iconic and loved tetras, neon tetras have bright blue and red stripes that stand out in any setting.
  • 6-15 Rummynose Tetras: Featuring a red “blushing” nose, these tetras stand out with their unique look.

When stocking a 15-gallon tank with tetras, it is essential to consider the compatibility of their temperament and environmental requirements with other tank mates. Doing so ensures a harmonious and thriving aquatic environment for every inhabitant.

Please note, the recommended water parameters for tetras will change between the various types. Always check the specific requirements of the type of tetra that you want to keep in your 15 gallon tank to set the tank up to meet the needs of the fish.

Different types of tetra that can thrive in a hexagon tank
Different Types Of Tetra That Can Thrive In A Hexagon Tank

Livebearers

A Molly Fish
A Molly Fish

Livebearers are a popular choice for 15-gallon aquariums. These small, colorful fish are known for their rapid breeding and easygoing nature. When stocking a livebearer tank, it is essential to consider the appropriate male to female ratio and species compatibility.

Different livebearers require slightly different water parameters to each other so always check the requirements for the specific type you keep.

If you are a beginner, we would highly recommend that you stick to a tank of just male fish. This will prevent any unwanted babies in your tank and most male livebearers have stronger coloration than the females.

You can use a 15 gallon tank as a breeding tank and we usually recommend that you keep two to three females per male.

Endler’s Livebearer

Endler's Livebearers
Endler’s Livebearers

Endler’s Livebearers are small and active fish that can add color and movement to your aquarium. In a 15-gallon tank, you can comfortably house 5-25 of these charming fish. Endler’s livebearers are usually one of the more hardy livebearers making them a great option for beginners.

Guppies

A Guppy
A Guppy

Guppies are another excellent choice for a 15-gallon aquarium. They come in a variety of colors and patterns, making them an attractive addition to any tank. It is possible to keep 4-9 guppies in a 15-gallon tank. We have a dedicated guppy care guide that can help you ensure you are providing your guppies with the best possible levels of care.

Platies

A Platy Fish
A Platy Fish

Platies are a hardy and versatile livebearer species that can be easily maintained in a 15 gallon tank. A general recommendation for platies would be to keep between 3-8 fish in a 15 gallon tank. Platies really are an under rated fish that can thrive in a 15 gallon tank with the species usually being pretty hardy and easy to care for.

Mollies

A Molly
A Molly

While it is typically not recommended to keep mollies in a 15-gallon tank due to their larger size, some hobbyists do successfully maintain a small number of mollies in such tanks. If you choose to house mollies in your 15-gallon-tank, aim to keep between 2-4 of these fish but we would not recommend them for beginners who are new to maintaining water parameters.

Rasboras

A Chilli Rasbora
A Chilli Rasbora

There are a number of different types of Rasboras that can work well in a 15-gallon tank. These small, colorful fish are known for being peaceful, and they enjoy swimming in schools. They can be a great addition to a community aquarium and can either serve as a complimentary school to a centerpiece fish or as the main focus of the tank.

To keep your Rasboras happy, it’s essential to provide them with a suitable environment. A well-planted tank with plenty of hiding spots is recommended, as this will mimic their natural habitat and help reduce stress. Additionally, maintaining stable water parameters and providing good quality water will contribute to the overall health and longevity of your Rasboras but recommended water parameters will change depending on the type of rasbora you keep.

When it comes to stocking your 15-gallon tank, you have a few options for commonly kept Rasboras. In a Fluval Flex 15-gallon tank, you may consider the following stocking options:

  • 6-20 Chilli Rasboras: These small and vibrant fish are ideal for a 15-gallon tank. They have a striking red color, making them an eye-catching addition to your aquarium.
  • 6-20 Galaxy Rasboras: Also known as Celestial Pearl Danio, these fish feature a beautiful pattern of blue and white speckles on their bodies, making them an attractive choice for a community tank.
  • 6-18 Harlequin Rasboras: With their distinct black marking on a silver to golden background, these fish are a popular choice for aquarists. Harlequin Rasboras are known for their ease of care and stunning appearance.

Remember that a small school of Rasboras works well as a complimentary school to a centerpiece fish, while a large school of Rasboras can be the main focus of your tank. Regardless of the type of Rasboras you choose, ensure that the tank is properly set up and maintained to guarantee the happiness and health of your fish.

Kuhli Loaches

A Kuhli Loach
A Kuhli Loach

Kuhli loaches (Pangio kuhlii) are unique tropical fish native to freshwater streams in Southeast Asia, such as Malaysia, Thailand, and Borneo. They belong to the Cobitidae family and are sometimes referred to as Coolie or Leopard loaches.

A group of 5 kuhli loaches can work well as the cleanup crew for your 15-gallon tank. These fish usually grow to about 3 inches in an aquarium and can reach up to 5 inches in the wild. They are bottom dwellers, which means they generally occupy the lower level of your tank and leave the top and middle levels free for other fish species to inhabit.

The specific type of substrate you use in your tank is important when keeping kuhli loaches but a fine sand substrate will usually be the best option.

Being nocturnal creatures, kuhli loaches are quite active during the night, while they tend to hide away during the day, reducing the chances of aggression in your tank. They prefer a water temperature of 75-86°F (24-30°C) and can adapt to a wide range of pH and GH levels. To accommodate their natural behavior, it is essential to provide them with plenty of hiding spots and aquarium plants in their habitat.

A Kuhli Loach

These peaceful and tranquil bottom dwellers coexist well with other non-aggressive tank mates. When it comes to feeding, kuhli loaches enjoy a variety of foods, including pellets, flakes, and live or frozen treats like brine shrimp and bloodworms. They are known to be affectionate with their keepers and may even take treats from their fingers.

In summary, kuhli loaches are excellent fish to include in your 15-gallon aquarium setup. They not only serve as an efficient cleanup crew but also contribute to a peaceful and diverse aquatic environment for various species due to their non-aggressive, nocturnal, and bottom-dwelling characteristics.

Here are our recommended water parameters for kuhli loaches:

Water Temperature: 72 to 79°F (22-26°C)
Water Flow: Still-Low
pH: 6.0-75.
GH: 4-8 dGH
KH: 2- 5 dkH
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: <15ppm

Cherry Barbs

A Cherry Barb
A Male Cherry Barb

Cherry Barbs are an excellent choice for a 15-gallon aquarium, as they are beautiful, active, and generally low-maintenance fish. These small, colorful creatures are native to Sri Lanka and are known to add vibrancy and life to any community tank.

Unlike many other types of barb, cherry barbs are relatively friendly and can often work well in a correctly stocked and planted tank.

In a 15-gallon tank, one can accommodate a small school of 6-12 Cherry Barbs, depending on the presence of other tank mates. If a secondary school of different fish species is desired, a group of 6 Cherry Barbs will thrive happily. Alternatively, if a single-species tank is preferred, a larger school of 12 Cherry Barbs can be maintained without any issue.

Cherry Barbs are schooling fish that require a well-planted aquarium with ample hiding places for them to feel secure. When setting up the tank, incorporate a variety of plants and decorations to provide both cover and open swimming areas. This will allow the Cherry Barbs to exhibit their natural behavior and feel at ease within the tank environment.

Cherry Barbs
Female Cherry Barbs

When it comes to feeding Cherry Barbs, they are known to be omnivores with a preference for both plant-based and protein-rich foods. A varied diet consisting of high-quality flakes, pellets, live, or frozen foods such as bloodworms, brine shrimp, and daphnia will ensure that their nutritional needs are met and help maintain their vibrant coloration.

For a harmonious multi-species aquarium, it is essential to select compatible tank mates for Cherry Barbs. Suitable companions include other peaceful schooling fish like Tetras and Rasboras. It is essential to avoid aggressive or overly large species that may prey on or intimidate these peaceful fish.

Here are our recommended water parameters for cherry barbs:

Water Temperature: 73 °F to 81 °F (23 °C to 27 °C)
Water Flow: Low
pH: 6.0-7.5
GH: 5–19 dGH
KH: 4-10 dkH
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: <15 ppm

In summary, Cherry Barbs make a fantastic addition to a 15-gallon tank, whether as a primary school or secondary school alongside other suitable tank mates. Their adaptability, striking appearance, and peaceful demeanor make them a popular choice and a joy to observe in any aquarium setting.

Albino Cory

An Albino Cory
An Albino Cory

Albino Cory Catfish make a great addition to a 15-gallon tank, providing an attractive and active bottom-dwelling species. These fish are known for their peaceful temperament and can coexist with other small, peaceful fish species.

In a 15-gallon tank, it is recommended to have a group of 6-10 Albino Cory Catfish. This number ensures their social nature is encouraged and allows them to exhibit their usual swimming behaviors, as they tend to be surprisingly active for bottom dwellers.

When kept in a group, these fish can often be seen swimming all around the tank, adding entertainment and diversity to your aquarium.

Due to the recommended number of Albino Cory Catfish, there may be limited space left for other species in a 15-gallon tank. The ideal tankmates for Albino Cory Catfish include small schooling fish such as tetras or rasboras. However, if you wish to prioritize a larger school of Albino Cory Catfish, you can create a species-specific tank, where the primary focus is on this species.

Due to being bottom-dwelling scavengers, we highly recommend that you use fine sand as your substrate of choice but fine gravel can work well too.

Here are our recommended water parameters for albino cory catfish:

Water Temperature: 70-81°F (21-27°C)
Water Flow: Slow-Moderate
pH: 7-8
GH: 2–20 dGH
KH: 3-10 dKH
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: <10 ppm

Danios

A Danio
A Danio

One of the best choices for a 15-gallon tank is the danio with this being a very underrated fish for smaller tanks, especially amongst beginners. Danios belong to the Cyprinidae family and include 27 varieties, with many showcasing striking colors and patterns.

In a 15-gallon tank, you can accommodate up to eight zebra danios. This is based on the general rule that one inch of fish requires one gallon of water. Typically, a fully-grown zebra danio measures about two inches in length. Other small danios, such as the dwarf spotted danio (Danio nigrofasciatus), also fit well in a 15-gallon tank. They usually reach an adult size of about 2 inches (4.5 cm) or even smaller.

It is essential to keep at least six danios in the tank, as they are schooling fish and prefer to swim together in groups. Socializing with other fish of the same species is crucial for their well-being. A well-planted tank with ample hiding spots enhances their habitat and enables them to feel more secure.

GloFish Danios
GloFish Danios

When considering tank mates, you can select compatible species like cardinal tetras, neon tetras, swordtails, cory catfish, clown plecos, guppies, and platies. Some suitable invertebrates include mystery snails, nerite snails, ramshorn snails, bladder snails, and Malaysian trumpet snails.

Check the specific water parameters for the type of danios you intend to keep in your tank as different types of danio need slightly different water parameters.

In conclusion, danios are an excellent choice for a 15-gallon tank. Be sure to select smaller types of danios to accommodate the tank size and provide them with suitable tank mates and habitat conditions for a thriving aquarium experience.

White Cloud Mountain Minnow

White Cloud Mountain Minnows
White Cloud Mountain Minnows

White Cloud Mountain Minnows are a popular option for 15-gallon tanks, particularly for beginners or people who don’t want to use a heater in their tank. These small, peaceful freshwater fish can thrive in a variety of water parameters, making them an ideal addition to your aquarium.

In a 15-gallon tank, you can comfortably house 6-20 White Cloud Mountain Minnows. These fish are known for their hardiness and adaptability, which makes them beginner-friendly.

To accommodate a variety of tank mates, it is recommended to keep a smaller school of White Cloud Mountain Minnows. However, if you prefer a species-specific tank, you can easily maintain a school of 15 or more fish in a 15-gallon tank. These fish are very active and enjoy swimming together in a group, adding a lively dynamic to your aquarium.

White Cloud Mountain Minnow
A White Cloud Mountain Minnow

White Cloud Mountain Minnows are also known for their vibrant appearance, featuring a silver or gold base color with hints of red and green iridescence. This unique coloration makes them an attractive addition to any freshwater tank, and their peaceful nature allows them to coexist well with other fish species.

Here are our recommended water parameters for white cloud mountain minnows:

Water Temperature: 65-77°F (18-25°C)
Water Flow: Low-Moderate
pH: 6.0—8.0
GH: 5-19 dGH
KH: 2-15 dKH
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: <10 ppm

In summary, White Cloud Mountain Minnows are an excellent choice for a 15-gallon tank due to their beginner-friendly nature, adaptability, and peaceful temperament. Whether you prefer a smaller school with various tank mates or a species-specific tank with a larger group, these fish will undoubtedly enhance your aquarium experience.

Neocaridina Shrimp

Different types of shrimp that work well in shrimp tanks

Most types of neocaridina shrimp can work well in a 15 gallon tank but they are usually used as a secondary addition to fish rather than a main attraction unless you are setting up a shrimp breeding tank. Cherry shrimp are usually the best option for beginners due to their affordability and ease of care but there are a huge range of neocaridina shrimp available..

Cherry shrimp, also known as red cherry shrimp, are small freshwater invertebrates that come from the streams and ponds of Taiwan. Their vibrant red coloration makes them a popular choice for aquarium enthusiasts. These shrimp have low bioload requirements, with a common recommendation being 2-5 shrimp per gallon. Given their small size, they can comfortably fit in a 15-gallon tank.

When considering tank mates for neocaridina shrimp, it’s crucial to remember that some species might prey on the shrimp due to their small size. Potential tank mates that are generally safe for neocaridina shrimp include bronze cory, ember tetra, endlers fish, pencil fish, kuhli loach, betta fish, and other invertebrates such as snails.

Cherry Shrimp
Cherry Shrimp

The ideal tank setup for neocaridina shrimp should have stable water parameters, as fluctuations can be detrimental to their health. Ensuring that the tank is well-cycled helps maintain a stable living environment for these shrimp as well as their tank mates.

Here are our recommended water parameters for red cherry shrimp but other types of neocaridina shrimp can have slightly different requirements:

Water Temperature: 57-86F
Water Flow: Still-Low
pH: 6.5-8
GH: 6-8 dGH
KH: 2-8 dKH
Ammonia: 0 ppm
Nitrite: 0 ppm
Nitrate: < 20ppm

In summary, adding neocaridina shrimp to a 15-gallon tank is a great way to enhance visual appeal and variety. Cherry shrimp, in particular, can be a good choice due to their cost-effectiveness and ease of care. However, always be mindful of potential predatory tank mates to keep your shrimp safe and thriving.

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