Not all fish belong in a massive, high-maintenance tank. Some are tiny, beautiful, and full of personality—perfect for small aquariums that fit right on your desk or shelf.
These little swimmers don’t just survive in compact spaces; they thrive. From brilliantly colored bettas to quirky little catfish, there’s a fish for every kind of aquarist, whether you’re a beginner or a seasoned pro.
But small doesn’t mean boring. Some of these fish are territorial, some are social, and a few even have their own quirky habits, like building bubble nests or changing colors.
If you’re looking to add life and movement to a small tank without overwhelming it, these 18 fish are the perfect match!
Betta Fish
Betta fish, known for their stunning colors and long, flowing fins, are a popular choice for small aquariums. These fish thrive in tanks as small as five gallons, making them perfect for limited spaces. Bettas are labyrinth fish, meaning they can breathe air, allowing them to survive in low-oxygen environments.
Their solitary nature suits them well to being the only fish in a tank, avoiding aggression with other fish. Bettas are relatively easy to care for, needing regular water changes and a balanced diet. Their beauty and low maintenance make them a favorite among aquarium enthusiasts.
Neon Tetra
Neon Tetras are small, vibrant fish that bring a splash of color to any aquarium with their iridescent blue and red stripes. They are peaceful, schooling fish that thrive in groups, creating a lively display in tanks as small as ten gallons.
These tetras prefer slightly acidic water and enjoy a densely planted environment which mimics their natural habitat. Feeding them a varied diet of small pellets and live foods helps maintain their vivid colors. Neon Tetras are an excellent choice for beginners due to their hardy nature and easy-going temperament.
Guppy
Guppies are lively and colorful fish, renowned for their wide variety of patterns and tail shapes. They adapt well to small aquariums, needing at least five gallons to thrive. Guppies are peaceful and can coexist with other small fish species.
These fish breed easily, so it’s essential to manage their population to avoid overcrowding. Guppies prefer clean water and a varied diet, which helps keep their colors vibrant. With proper care and a suitable tank environment, guppies can be a delightful and dynamic addition to any small aquarium.
Zebra Danio
Zebra Danios are small, hardy fish known for their horizontal zebra-like stripes, making them an attractive addition to small aquariums. They are active and social, preferring to live in groups of at least five, which helps reduce stress.
These fish are adaptable to various water conditions and temperatures, meaning they can thrive in different aquarium setups. Zebra Danios are also known for their playful nature, often swimming quickly across the tank. Their easy-going temperament and resilience make them a great choice for both beginners and experienced aquarists.
Corydoras Catfish
Corydoras Catfish, often simply called Corys, are small, peaceful bottom-dwellers perfect for small aquariums. They thrive in groups, which encourages natural behavior and activity. Corys are excellent at cleaning up leftover food, contributing to a healthier tank environment.
These catfish prefer soft, sandy substrates to protect their sensitive barbels. With a range of species offering different patterns and sizes, they add variety to the tank. Corydoras are easy to care for, needing clean water and occasional feedings of sinking pellets or wafers. Their gentle nature makes them a beloved choice.
Endler’s Livebearer
Endler’s Livebearers are small, vibrant fish closely related to guppies, offering a burst of color to any small aquarium. They are hardy, adaptable, and thrive in tanks as small as five gallons. These fish are social and prefer being in groups, making them an active presence in the tank.
Endler’s are easy to breed, so managing their numbers is essential to prevent overcrowding. They thrive on a balanced diet of flake food and occasional live foods. Endler’s Livebearers are an excellent choice for aquarists looking for colorful, low-maintenance fish.
Harlequin Rasbora
Harlequin Rasboras are small, peaceful fish known for their striking black triangular markings against a silvery body. They are schooling fish that thrive in groups, enhancing their color and activity. A tank of ten gallons or more can accommodate a school of these fish comfortably.
These rasboras prefer soft, acidic water and a densely planted environment with plenty of swimming space. A diet of high-quality flakes and occasional live food keeps them healthy. Harlequin Rasboras are a perfect match for community aquariums due to their gentle nature and stunning appearance.
Cherry Barb
Cherry Barbs are small, elongated fish, with males displaying vivid red hues that brighten up any small aquarium. They are peaceful fish, suitable for community tanks, and should be kept in groups to exhibit natural behavior.
These barbs thrive in tanks with plenty of plants and hiding spots, mimicking their natural habitat. A balanced diet of flakes, pellets, and live food ensures their long-term health and color vibrancy. Cherry Barbs’ adaptability to different water conditions and their striking color make them a popular choice among fishkeepers.
Pygmy Corydoras
Pygmy Corydoras are miniature catfish that are perfect for the bottom of small aquariums. These social fish should be kept in groups, where they exhibit shoaling behaviors and contribute to the tank’s dynamic.
They prefer soft substrates to protect their delicate barbels and thrive in aquariums with clean water. Feeding on small sinking pellets and occasional live or frozen foods keeps them healthy. Their gentle demeanor and active nature make Pygmy Corydoras a charming addition to a small tank, appealing to both novice and experienced aquarists.
White Cloud Mountain Minnow
White Cloud Mountain Minnows are small, cold-water fish that adapt well to small aquariums, even those without heaters. Known for their shimmering scales and red fins, they are peaceful and best kept in groups.
These minnows thrive in cooler temperatures and can coexist with other non-aggressive fish. A varied diet of flakes and live foods helps maintain their vibrant coloration. Their resilience and easy care requirements make them a favorite for small tanks, especially for those looking for interesting fish that don’t need heated water.
Dwarf Gourami
Dwarf Gouramis are small, brilliantly colored fish, perfect for enhancing the aesthetics of a small aquarium. They are labyrinth fish, which allows them to thrive in low-oxygen environments by gulping air from the surface.
These gouramis enjoy tanks with plants and gentle water flow, mimicking their natural habitat. They are generally peaceful but can be territorial towards other males, so careful tankmate selection is crucial. A diet of flakes, pellets, and occasional live foods ensures their health and vibrancy. Dwarf Gouramis are a stunning and rewarding choice for aquariums.
Otocinclus Catfish
Otocinclus Catfish, often called Oto Cats, are small, efficient algae eaters perfect for maintaining cleanliness in small aquariums. These peaceful fish prefer to be in groups and are known for their active feeding behavior.
They thrive in tanks with stable water conditions and plenty of surfaces to graze on. Feeding them with algae wafers supplements their diet if natural algae are scarce. Their ability to clean and their non-aggressive nature make them a valuable addition to any small tank, especially for aquarists struggling with algae management.
Celestial Pearl Danio
Celestial Pearl Danios, also known as Galaxy Rasboras, are tiny, captivating fish with intricate spotted patterns reminiscent of a starry sky. They thrive in small aquariums with dense plant cover and stable water conditions.
These fish are generally peaceful but can be shy, preferring to stay in groups to feel secure. A varied diet of high-quality micro-pellets and live foods helps maintain their health and vivid colors. Their stunning appearance and unique behaviors make Celestial Pearl Danios an intriguing choice for aquarists looking to add beauty and interest to a small tank.
Sparkling Gourami
Sparkling Gouramis are tiny, enchanting fish known for their iridescent scales and subtle, jewel-like colors. They are labyrinth fish, allowing them to breathe air and thrive in low-oxygen environments.
These gouramis prefer heavily planted tanks with calm water and plenty of hiding spots. They are peaceful and can coexist with other small, non-aggressive fish. A diet of small pellets and live foods keeps them healthy. Sparkling Gouramis’ unique beauty and adaptability make them an excellent choice for those seeking a peaceful and colorful addition to their small aquarium.
Pea Puffer
Pea Puffers are one of the smallest pufferfish species, known for their inquisitive nature and endearing appearance. They thrive in small, well-planted tanks and require careful attention to water quality.
These puffers can be territorial and are best kept alone or with other non-aggressive fish. A diet of live or frozen foods such as bloodworms and snails is essential for their health. Despite their small size, Pea Puffers are full of personality, making them a fascinating choice for aquarists looking to add character to their small setups.
Killifish
Killifish are small, vibrant fish known for their remarkable color patterns and energetic behavior. They are adaptable to various water conditions, making them suitable for small aquariums.
These fish are generally peaceful, though they can be territorial during breeding. A tank with plenty of hiding spots and a diverse diet of live foods ensures their well-being. Killifish are often kept in species-specific tanks due to their unique care requirements. Their striking appearance and lively nature make them a captivating choice for dedicated aquarists seeking challenge and beauty.
Platy
Platies are small, colorful fish known for their hardy nature and ease of care, making them ideal for beginners. They thrive in community tanks and come in a wide variety of colors and patterns, adding vibrancy to any setup.
These fish are livebearers, so managing their population is vital to prevent overcrowding. Platies prefer a varied diet of flakes and live foods. Their peaceful temperament and adaptability to different water conditions make them a popular choice for small aquariums, offering both beauty and ease of maintenance.
Kuhli Loach
Kuhli Loaches are slender, eel-like fish that add a unique touch to small aquariums. They are nocturnal and prefer to hide during the day, coming out to forage at night.
These loaches thrive in tanks with soft substrates and plenty of hiding spots like caves and dense plants. A diet of sinking pellets and live foods keeps them healthy. Kuhli Loaches are peaceful and can coexist with other non-aggressive fish. Their interesting behavior and unique appearance make them a fascinating addition to a small, community tank.