Aquarium Fish & Species Guide
Complete care guides with tank size requirements, water parameters, diet, and compatible tank mates for every species.
Freshwater Fish
Guppy
Poecilia reticulata
Guppies are colorful, hardy livebearers that are perfect for beginners. Males sport spectacular tail patterns in every color imaginable, while females are larger and less colorful. They breed prolifically — a single female can produce 20–50 fry every month — so plan accordingly or keep only males.
Betta Fish
Betta splendens
The Betta fish (Siamese fighting fish) is one of the most popular freshwater aquarium fish in the world, known for its stunning flowing fins and vibrant colors. Males are territorial and should be kept alone or with carefully chosen tank mates. Despite their reputation as low-maintenance fish, bettas thrive best in heated, filtered tanks of at least 5 gallons.
Goldfish
Carassius auratus
Goldfish are among the longest-kept ornamental fish, with a history spanning over 1,000 years. Despite their reputation as easy, bowl-dwelling pets, goldfish actually require spacious tanks with strong filtration. They are cold-water fish that should not be kept with tropical species. Common varieties include comets, fantails, orandas, and ryukins.
Neon Tetra
Paracheirodon innesi
The Neon Tetra is arguably the most popular freshwater aquarium fish in the hobby. Their electric blue stripe and red tail create a stunning display, especially in large schools against a planted backdrop. Hardy, peaceful, and easy to care for, neon tetras are perfect for beginners and make excellent community tank members.
Flowerhorn Cichlid
Hybrid
The Flowerhorn Cichlid (Hybrid) is a intermediate-level freshwater fish growing to 12 inches. Aggressive temperament, minimum 55 gallon tank.
Silver Arowana
Osteoglossum bicirrhosum
The Silver Arowana (Osteoglossum bicirrhosum) is a advanced-level freshwater fish growing to 36 inches. Aggressive temperament, minimum 125 gallon tank.
Electric Yellow Cichlid
Labidochromis caeruleus
The Electric Yellow Cichlid (Labidochromis caeruleus) is a intermediate-level freshwater fish growing to 4 inches. Semi-aggressive temperament, minimum 30 gallon tank.
Clown Loach
Chromobotia macracanthus
The Clown Loach (Chromobotia macracanthus) is a intermediate-level freshwater fish growing to 12 inches. Peaceful temperament, minimum 75 gallon tank.
Pea Puffer
Carinotetraodon travancoricus
Pea puffers are the smallest freshwater pufferfish in the world, growing to just 1 inch. Despite their tiny size, they have big personalities — they are curious, intelligent, and surprisingly aggressive. They are best kept in species-only tanks and require live or frozen food.
Peacock Cichlid
Aulonocara spp.
The Peacock Cichlid (Aulonocara spp.) is a intermediate-level freshwater fish growing to 6 inches. Semi-aggressive temperament, minimum 55 gallon tank.
Boesemani Rainbowfish
Melanotaenia boesemani
The Boesemani Rainbowfish (Melanotaenia boesemani) is a beginner-level freshwater fish growing to 4.5 inches. Peaceful temperament, minimum 30 gallon tank.
Angelfish
Pterophyllum scalare
Freshwater angelfish are elegant, tall-bodied cichlids that are a centerpiece in many community aquariums. They come in many color varieties including silver, marble, koi, and black. While generally peaceful, they become territorial when breeding and will eat small fish like neon tetras.
Apistogramma
Apistogramma cacatuoides
The Apistogramma (Apistogramma cacatuoides) is a intermediate-level freshwater fish growing to 3 inches. Semi-aggressive temperament, minimum 20 gallon tank.
Otocinclus Catfish
Otocinclus spp.
Otocinclus catfish (otos) are tiny, peaceful algae eaters that are incredibly effective at controlling soft green algae and diatoms in planted tanks. They are the gold standard for planted tank algae control, often preferred over larger plecos. However, they are somewhat delicate and require established, well-maintained aquariums.
Rope Fish
Erpetoichthys calabaricus
The Rope Fish (Erpetoichthys calabaricus) is a intermediate-level freshwater fish growing to 15 inches. Peaceful temperament, minimum 55 gallon tank.
Senegal Bichir
Polypterus senegalus
The Senegal Bichir (Polypterus senegalus) is a intermediate-level freshwater fish growing to 12 inches. Semi-aggressive temperament, minimum 40 gallon tank.
Bristlenose Pleco
Ancistrus spp.
The Bristlenose Pleco is the most popular pleco species for home aquariums, and for good reason — they stay small (4–5 inches vs 12–24 inches for common plecos), are excellent algae eaters, and are hardy and easy to care for. Males develop distinctive bristle-like growths on their nose, which is how they get their name.
Dwarf Gourami
Trichogaster lalius
Dwarf gouramis are stunning labyrinth fish with vibrant red and blue striped patterns. Like bettas, they can breathe atmospheric air. Males are colorful while females are silvery. They are generally peaceful but males can be territorial with each other.
Ember Tetra
Hyphessobrycon amandae
Ember tetras are tiny, fiery-orange schooling fish that add a warm glow to planted tanks. At under 1 inch, they are perfect for nano tanks and make excellent companions for shrimp.
Cardinal Tetra
Paracheirodon axelrodi
Cardinal tetras look similar to neon tetras but have a red stripe that extends the entire length of their body (vs only the back half in neons). They prefer softer, more acidic water and are slightly more delicate, but their deeper coloration makes them highly sought after.
Bolivian Ram
Mikrogeophagus altispinosus
The Bolivian Ram (Mikrogeophagus altispinosus) is a beginner-level freshwater fish growing to 3.5 inches. Peaceful temperament, minimum 20 gallon tank.
Chili Rasbora
Boraras brigittae
The Chili Rasbora (Boraras brigittae) is a intermediate-level freshwater fish growing to 0.8 inches. Peaceful temperament, minimum 5 gallon tank.
Denison Barb
Sahyadria denisonii
The Denison Barb (Sahyadria denisonii) is a intermediate-level freshwater fish growing to 6 inches. Peaceful temperament, minimum 55 gallon tank.
Yoyo Loach
Botia almorhae
The Yoyo Loach (Botia almorhae) is a intermediate-level freshwater fish growing to 6 inches. Peaceful temperament, minimum 30 gallon tank.
Pictus Catfish
Pimelodus pictus
The Pictus Catfish (Pimelodus pictus) is a intermediate-level freshwater fish growing to 5 inches. Peaceful temperament, minimum 55 gallon tank.
Glass Catfish
Kryptopterus vitreolus
The Glass Catfish (Kryptopterus vitreolus) is a intermediate-level freshwater fish growing to 5 inches. Peaceful temperament, minimum 20 gallon tank.
African Cichlid
Various (Mbuna, Peacock, Hap)
African cichlids from Lakes Malawi, Tanganyika, and Victoria are among the most colorful freshwater fish. They are active, intelligent, and aggressive — requiring specific tank setups with plenty of rock formations and overstock strategies to manage aggression.
Molly
Poecilia sphenops
Mollies are versatile livebearers that come in many varieties including black, dalmatian, balloon, and sailfin. They prefer hard, alkaline water and can even tolerate brackish conditions. They are active, personable fish that breed easily.
Tiger Barb
Puntigrus tetrazona
Tiger barbs are energetic, boldly-striped schooling fish that add constant motion and personality to aquariums. Their orange body with four distinctive black vertical stripes is instantly recognizable. They are notorious fin nippers when kept in small groups, but this behavior is easily managed by keeping 8+ together in a spacious tank.
German Blue Ram
Mikrogeophagus ramirezi
German blue rams are one of the most beautiful dwarf cichlids, with iridescent blue and gold coloration, a distinctive black spot, and red-highlighted fins. Despite being cichlids, they are remarkably peaceful and make excellent centerpiece fish for planted community tanks. They do require warm, soft water and are more sensitive than typical community fish.
Boesemani Rainbowfish
Melanotaenia boesemani
Boesemani rainbowfish are among the most colorful freshwater fish available. Males display a stunning gradient from steel blue on the front half to bright orange-gold on the back half. They are active, hardy schooling fish that reach a respectable 4–5 inches and look absolutely spectacular in schools of 8+ under good lighting.
Honey Gourami
Trichogaster chuna
Honey gouramis are the gentlest gourami species — even more peaceful than their larger dwarf gourami relatives. Males display a warm honey-gold coloration that deepens to rich amber when breeding. At only 2 inches, they are perfect for nano community tanks. They are also significantly hardier than dwarf gouramis, which suffer from the iridovirus (DGIV).
Hillstream Loach
Sewellia lineolata
Hillstream loaches are fascinating flat-bodied fish that resemble tiny stingrays. They are specialized for life in fast-flowing, oxygen-rich streams and use their modified pelvic and pectoral fins to grip smooth rocks in strong current. Their unique appearance, algae-eating habits, and cool-water preference make them popular with experienced fishkeepers looking for something different.
Celestial Pearl Danio
Danio margaritatus
Celestial pearl danios (also called galaxy rasboras) are tiny, jewel-like fish discovered in Myanmar in 2006. Their dark blue body is covered in iridescent pearl-white spots, with bright orange-red fins striped with black. Despite their exotic appearance, they are hardy and easy to care for — one of the hobby's best-kept secrets for nano tanks.
Zebra Danio
Danio rerio
Zebra danios are one of the hardiest, most energetic freshwater fish in the hobby. Their horizontal blue and silver stripes and constant darting motion add life to any aquarium. They tolerate a remarkably wide range of conditions, from cool subtropical to warm tropical temperatures, making them ideal for beginners. They are also the species used as the basis for GloFish.
Green Neon Tetra
Paracheirodon simulans
The Green Neon Tetra (Paracheirodon simulans) is a intermediate-level freshwater fish growing to 1 inches. Peaceful temperament, minimum 10 gallon tank.
Sparkling Gourami
Trichopsis pumila
The Sparkling Gourami (Trichopsis pumila) is a intermediate-level freshwater fish growing to 1.5 inches. Peaceful temperament, minimum 10 gallon tank.
Synodontis Catfish
Synodontis multipunctatus
The Synodontis Catfish (Synodontis multipunctatus) is a intermediate-level freshwater fish growing to 8 inches. Peaceful temperament, minimum 30 gallon tank.
Rubber Lip Pleco
Chaetostoma formosae
The Rubber Lip Pleco (Chaetostoma formosae) is a beginner-level freshwater fish growing to 4.5 inches. Peaceful temperament, minimum 20 gallon tank.
Panda Corydoras
Corydoras panda
The Panda Corydoras (Corydoras panda) is a beginner-level freshwater fish growing to 2 inches. Peaceful temperament, minimum 10 gallon tank.
Rummy Nose Tetra
Hemigrammus rhodostomus
Rummy nose tetras are considered the ultimate schooling fish in the freshwater hobby. Their tight, synchronized formations are unmatched by any other tetra species. The vivid red nose serves as a health indicator — bright red means healthy, pale red means stressed. They prefer soft, acidic water and are slightly more demanding than neon tetras.
Discus
Symphysodon spp.
Discus are widely considered the king of freshwater aquarium fish. Their disk-shaped body, vivid colors, and graceful swimming make them the ultimate showpiece. However, they are among the most demanding freshwater fish to keep, requiring warm, soft, exceptionally clean water, frequent feedings, and a stress-free environment. Discus are not recommended for beginners.
Three Spot Gourami
Trichopodus trichopterus
The Three Spot Gourami (Trichopodus trichopterus) is a beginner-level freshwater fish growing to 6 inches. Semi-aggressive temperament, minimum 20 gallon tank.
Sterbai Corydoras
Corydoras sterbai
The Sterbai Corydoras (Corydoras sterbai) is a beginner-level freshwater fish growing to 2.5 inches. Peaceful temperament, minimum 20 gallon tank.
Harlequin Rasbora
Trigonostigma heteromorpha
Harlequin rasboras are elegant, copper-colored schooling fish with a distinctive black triangular patch on their body. They are one of the most peaceful and hardy community fish available, making them ideal for beginners. In schools of 8+, they display beautiful coordinated swimming behavior.
Platy
Xiphophorus maculatus
Platies are colorful, hardy livebearers that come in dozens of color varieties. They are extremely easy to care for, breed readily, and get along with virtually all peaceful community fish. Perfect for beginners.
Black Skirt Tetra
Gymnocorymbus ternetzi
Black skirt tetras (also sold as black widow tetras) are hardy, easy-to-care-for schooling fish with a distinctive flowing black anal fin that gives them their name. They come in natural silver-and-black and various dyed/modified versions (GloFish). The natural form is the healthiest choice. They can be mild fin nippers in small groups but are generally well-behaved community fish.
Congo Tetra
Phenacogrammus interruptus
Congo tetras are the showstoppers of the tetra family. Males develop spectacular flowing fins with an iridescent rainbow sheen that shifts from blue to gold to green under aquarium lighting. They are larger than most tetras (up to 3.5 inches) and need a spacious, well-planted tank to display their full beauty. Peaceful but shy — they thrive with calm tank mates.
Cherry Barb
Puntius titteya
Cherry barbs are one of the most peaceful barb species, making them ideal for community tanks. Males develop a deep cherry-red coloration when mature and in breeding condition, while females remain more subdued with brown-pink tones. Unlike their more boisterous relatives like tiger barbs, cherry barbs are gentle, shy, and compatible with even the most delicate tank mates.
Swordtail
Xiphophorus hellerii
Swordtails are hardy, colorful livebearers named for the distinctive elongated lower tail fin (the 'sword') found on males. They come in many color varieties including red, pineapple, marigold, and tuxedo. Larger than guppies but just as easy to care for, swordtails are excellent community fish that prefer hard, alkaline water.
Jack Dempsey Cichlid
Rocio octofasciata
Named after the legendary boxer, Jack Dempsey cichlids are large, territorial Central American cichlids with iridescent blue-green spangles across their dark body. They are aggressive, intelligent, and interactive — many owners report them coming to the glass to greet them. The electric blue Jack Dempsey variant is significantly less aggressive and more colorful.
Convict Cichlid
Amatitlania nigrofasciata
Convict cichlids are tough, prolific Central American cichlids with distinctive black and white vertical stripes — earning them the 'convict' name. They are extremely hardy, breed readily (almost uncontrollably), and are highly aggressive for their size, especially when protecting fry. They are excellent for beginners who want to keep cichlids but should not be mixed with peaceful community fish.
Silver Dollar Fish
Metynnis hypsauchen
Silver dollars are large, disc-shaped, peaceful schooling fish related to piranhas — but entirely herbivorous. Their shimmering silver body catches light beautifully in motion. They are excellent dither fish for large cichlid tanks because their calm, open-water swimming behavior helps reduce cichlid aggression. Warning: they will eat every live plant in your tank.
Pearl Gourami
Trichopodus leeri
Pearl gouramis are widely considered the most beautiful gourami species, with a body covered in iridescent pearl-like spots over a brown-silver base. Males develop a stunning red-orange chest and throat during breeding displays. They are one of the most peaceful gouramis, making them excellent centerpiece fish for community tanks.
White Cloud Mountain Minnow
Tanichthys albonubes
White cloud mountain minnows are hardy, colorful cold-water fish that are perfect for unheated aquariums and goldfish companions. Their small size, brilliant red fins, and iridescent lateral line make them surprisingly attractive for such a hardy, easy-to-keep species. They are one of the few truly cold-water schooling fish available in the hobby.
Firemouth Cichlid
Thorichthys meeki
Firemouth cichlids are one of the most beginner-friendly Central American cichlids. Named for their striking red/orange coloration on the throat and belly, they are less aggressive than most cichlids of their size. When threatened, they flare their gill covers to display their bright red throat — a bluffing display that is far more bark than bite.
Endler's Livebearer
Poecilia wingei
Endler's livebearers are close relatives of guppies but stay smaller and display even more intense neon coloration. Males are tiny but spectacularly colored. They breed prolifically and are perfect for nano tanks.
Serpae Tetra
Hyphessobrycon eques
Serpae tetras are vibrant blood-red schooling fish with a distinctive black comma-shaped marking behind the gill plate. While beautiful, they have a reputation as fin nippers — especially in small groups. Keeping them in schools of 8+ in a spacious tank significantly reduces this behavior. They add bold color to community tanks when kept properly.
Clown Pleco
Panaqolus maccus
Clown plecos are beautiful, small plecos with striking orange and black striped patterns. At only 3.5 inches max size, they are perfect for 20-gallon and larger community tanks. Unlike many pleco species, they are primarily wood eaters rather than algae eaters — driftwood is an essential part of their setup. They are shy, nocturnal, and make excellent additions to planted tanks.
Pygmy Corydoras
Corydoras pygmaeus
Pygmy corydoras are tiny, adorable catfish that max out at just 1 inch. Unlike other corys that stay on the bottom, pygmy corys are unique in that they frequently swim in the mid-water column, hovering in groups like tiny helicopters. They are perfect for nano tanks and shrimp tanks, and their micro-schooling behavior is endlessly entertaining.
Corydoras Catfish
Corydoras spp.
Corydoras catfish are beloved bottom-dwelling community fish known for their adorable whiskered faces and playful schooling behavior. With over 160 described species, corys come in many varieties including bronze, albino, panda, pygmy, and sterbai. They are peaceful, hardy, and help keep the substrate clean.
Kuhli Loach
Pangio kuhlii
Kuhli loaches are eel-shaped, nocturnal bottom dwellers with striking black and orange/yellow banding. They are shy, peaceful, and love to burrow in sand and hide in tight spaces during the day. Despite their snake-like appearance, they are completely harmless community fish that become much more active and visible when kept in groups.
Oscar Fish
Astronotus ocellatus
Oscars are large, intelligent South American cichlids often called 'water dogs' for their interactive personality. They recognize their owners, beg for food, and can be hand-fed. However, they grow fast, produce massive waste, and need at least a 75-gallon tank.
Shrimp, Snails & Invertebrates
Cherry Shrimp
Neocaridina davidi
Cherry shrimp are the most popular freshwater aquarium shrimp, prized for their vibrant red color and algae-eating habits. They are extremely hardy, breed readily in captivity, and make excellent additions to planted tanks. Available in multiple color grades from pale pink (regular) to deep crimson (Painted Fire Red).
Amano Shrimp
Caridina multidentata
Amano shrimp, named after legendary aquascaper Takashi Amano, are the best algae-eating shrimp available. They are larger than cherry shrimp and voraciously consume hair algae, soft green algae, and leftover food. They do not breed in freshwater.
Nerite Snail
Neritina spp.
Nerite snails are the best algae-eating snails for freshwater aquariums. They come in beautiful patterns (zebra, tiger, horned, olive) and will not reproduce in freshwater — making them the ideal pest-free algae cleanup crew. A single nerite can keep a 5-gallon tank virtually algae-free.
Blue Dream Shrimp
Neocaridina davidi var. Blue Dream
The Blue Dream Shrimp (Neocaridina davidi var. Blue Dream) is a beginner-level freshwater invertebrate growing to 1.5 inches. Peaceful temperament, minimum 5 gallon tank.
Rabbit Snail
Tylomelania spp.
The Rabbit Snail (Tylomelania spp.) is a beginner-level freshwater invertebrate growing to 4 inches. Peaceful temperament, minimum 20 gallon tank.
Bamboo Shrimp
Atyopsis moluccensis
The Bamboo Shrimp (Atyopsis moluccensis) is a intermediate-level freshwater invertebrate growing to 3 inches. Peaceful temperament, minimum 20 gallon tank.
Assassin Snail
Clea helena
Assassin snails are the natural pest snail control solution. They hunt and eat bladder snails, pond snails, Malaysian trumpet snails, and ramshorn snails. They breed slowly (unlike pest snails), have attractive yellow and dark brown striped shells, and are safe with fish and shrimp.
Skunk Cleaner Shrimp
Lysmata amboinensis
Skunk cleaner shrimp are one of the most useful invertebrates in reef tanks. They operate a 'cleaning station' where fish line up to have parasites, dead skin, and debris removed from their bodies and gills. This natural cleaning service helps keep fish healthy and disease-free. They are also strikingly beautiful with their red-and-white striped body and long white antennae.
Mystery Snail
Pomacea bridgesii
Mystery snails are popular aquarium snails known for their vibrant colors (gold, ivory, blue, purple, black), algae-eating ability, and entertaining personality. Unlike pest snails, they won't overrun your tank as they lay visible egg clutches above the waterline that are easy to control. They're peaceful, hardy, and safe for planted tanks.
