TankStockingFreshwater aquarium planner
Stock your aquarium with confidence.
Tell TankStocking your tank size and the fish you like. Get an instant, honest verdict on whether they'll actually thrive together — before you spend a penny or risk a life.
Stocking Planner
Add your fish and tank size, get an instant compatibility + stocking-level verdict with the reasons spelled out.
Open →
Volume Calculator
Work out how many gallons (and litres) your tank really holds — then send it straight to the planner.
Open →
How it works
The exact model behind the verdicts: bio-load, hard welfare blockers, plant handling, data sources and limits.
Open →Fish care guides
Featured freshwater fish
Hand-written, welfare-checked care guides for 126 freshwater species — tank size, temperament and temperature at a glance. The set rotates; browse the full 126-species fish list any time.
-
Rosy Barb
In breeding condition a male rosy barb flushes deep copper-rose along the flank - the colour the fish is named for, and a fair…
- 30 gal min
- Semi-aggressive
- 18–24°C
-
Chili Rasbora
A male chili rasbora is barely two centimetres of glowing red and black — one of the smallest fish in the trade, and a fish that…
- 5 gal min
- Peaceful
- 20–28°C
-
Lambchop Rasbora
That thin black hook along the tail-base — a narrow blade where the harlequin carries a broad triangle — is how you pick a true…
- 10 gal min
- Peaceful
- 23–28°C
-
Firemouth Cichlid
Corner a firemouth and it does not bite - it bluffs.
- 30 gal min
- Territorial
- 23–29°C
-
Molly (Common / Sailfin)
The molly is a hard-water, alkaline livebearer that grows bigger than most beginners expect and breeds faster than they plan for.
- 20 gal min
- Peaceful
- 24–28°C
-
German Blue Ram
Few aquarium fish are sold under a wider gap between promise and reality than the German blue ram.
- 20 gal min
- Peaceful
- 27–30°C
-
Least Killifish (Dwarf Livebearer)
Forget the name — the least killifish is no killifish at all.
- 5 gal min
- Peaceful
- 16–24°C
-
Sterbai Corydoras
Hold a sterbai up to the glass and the pattern reads backwards: a dark, domed head dusted with white-to-cream spots — the…
- 20 gal min
- Peaceful
- 24–28°C
-
Gold White Cloud Mountain Minnow
Strip off the gold coat and you have a white cloud mountain minnow — that is the whole truth of this fish.
- 15 gal min
- Peaceful
- 14–22°C
-
Paradise Fish
One of the first ornamental fish the West ever kept — imported to France in 1869, behind only the goldfish — the paradise fish…
- 20 gal min
- Aggressive
- 16–26°C
-
X-ray (Pristella) Tetra
You can see straight through it — the backbone and the silvery swim-bladder capsule (its Weberian apparatus) show plainly behind…
- 15 gal min
- Peaceful
- 22–28°C
-
Convict Cichlid
Few fish pack as much trouble into 12 centimetres as the convict.
- 40 gal min
- Aggressive
- 24–28°C
-
Mystery Snail
Gold, blue or ivory, and big for a tank snail, the mystery snail spends its day grazing algae, biofilm and detritus — and…
- 10 gal min
- Peaceful
- 20–28°C
-
Threadfin Rainbowfish
Picture a fish barely 4 cm long trailing dorsal and anal filaments more than twice its own body length, flicked like pennants in…
- 15 gal min
- Peaceful
- 22–30°C
-
Fancy Goldfish
Few fish carry a worse reputation than they deserve: the fancy goldfish is a coldwater pet that lives a decade or more and…
- 30 gal min
- Peaceful
- 18–23°C
-
Otocinclus
Drop an oto into a sparkling new tank and you have quietly signed its death warrant.
- 10 gal min
- Peaceful
- 20–26°C
-
Congo Tetra
The Congo tetra breaks the 'tetra equals nano fish' rule: males reach ~8 cm, their flanks flickering blue through gold to red as…
- 30 gal min
- Peaceful
- 23–28°C
-
Marbled Hatchetfish
A startled marbled hatchetfish does something no other community fish can: it drives a deep, keeled chest — pectoral 'wings'…
- 20 gal min
- Peaceful
- 24–28°C
-
Pygmy Corydoras
Forget what the bronze cory taught you about catfish.
- 10 gal min
- Peaceful
- 22–26°C
-
Glowlight Tetra
One copper-orange line runs the length of a near-transparent silver body, glowing like a lit filament against the gloom — and…
- 15 gal min
- Peaceful
- 24–28°C
-
Peacock Gudgeon
Behind the "peacock goby" label hides a small deception: this is not a goby at all but an eleotrid sleeper, Tateurndina…
- 15 gal min
- Peaceful
- 22–26°C
-
Cardinal Tetra
The cardinal tetra is the neon's brighter, warmer-blooded cousin — a blackwater shoaler whose red runs the full length of the…
- 15 gal min
- Peaceful
- 23–29°C
-
Neon Tetra
Almost everyone's first fish is a neon tetra, and almost everyone makes the same mistake: dropping a tiny Amazon blackwater…
- 10 gal min
- Peaceful
- 21–25°C
-
Yoyo Loach
Look at a young one side-on and the dark bars really do read Y-O-Y-O down its silver-gold flank — that pattern is the namesake,…
- 40 gal min
- Semi-aggressive
- 24–30°C
-
Bumblebee Goby
Black-and-gold bands like a wasp shrunk onto a fish barely a thumbnail long (~3-4 cm): that bumblebee suit is the easy part.
- 10 gal min
- Territorial
- 22–28°C
-
Dwarf Pufferfish (Pea Puffer)
A fully grown pea puffer is smaller than your thumbnail, yet it patrols the tank like a scaled-down predator — swivelling each…
- 5 gal min
- Semi-aggressive
- 22–28°C
-
Snakeskin Gourami
Those broken, oblique bars over a plain silver flank — the reticulation that reads like snakeskin and gives the fish its name —…
- 55 gal min
- Peaceful
- 22–30°C
-
Silvertip Tetra
Look for the fins: clean white tips dabbed onto the dorsal, anal and both tail lobes, as if each were dipped in paint, set…
- 20 gal min
- Semi-aggressive
- 23–28°C
-
Scarlet Badis
Few fish are sold as effortlessly as the scarlet badis and die as quietly.
- 10 gal min
- Peaceful
- 22–26°C
-
Odessa Barb
A bar of blazing ruby red runs the length of the male's silver flank, flaring brightest when two males square off — that racing…
- 20 gal min
- Semi-aggressive
- 16–26°C
-
Ghost Shrimp (Glass/Grass Shrimp)
Hold a ghost shrimp up to the light and you can watch dinner travel down its gut — the body really is that transparent, and that…
- 5 gal min
- Peaceful
- 18–28°C
-
Denison Barb (Roseline Shark)
That bold red-and-black racing stripe down a silver, torpedo-shaped body is what sells the Denison barb on sight — and the trade…
- 55 gal min
- Semi-aggressive
- 20–25°C
-
Lemon Tetra
Most aquarium tetras are slim red-and-blue torpedoes; the lemon tetra is the deeper-bodied, diamond-profiled exception — a…
- 20 gal min
- Peaceful
- 20–28°C
-
Chocolate Gourami
Chocolate gouramis sell themselves on sight — cream bands over a cocoa-brown body — then quietly disqualify most tanks, because…
- 15 gal min
- Peaceful
- 26–31°C
-
Clown Pleco
Drop a piece of bogwood into the tank and a clown pleco will spend its nights rasping at it — because wood is dinner here, not…
- 20 gal min
- Peaceful
- 23–28°C
-
Dwarf Chain Loach
At 5–6 cm, the dwarf chain loach is small enough to belong in an ordinary community tank — genuinely rare for a loach — and,…
- 20 gal min
- Peaceful
- 24–28°C
-
Peppered Corydoras
Charles Darwin scooped the first peppered corys from a stream near Buenos Aires, and the species has been in aquariums almost as…
- 20 gal min
- Peaceful
- 18–24°C
-
Brilliant Rasbora
'Brilliant' is a shop label, not a description — the real signature of Rasbora einthovenii is the bold dark 'long band' that…
- 29 gal min
- Peaceful
- 22–26°C
-
Sparkling (Pygmy) Gourami
Few aquarium fish announce themselves by sound, and fewer still are this tiny: at roughly 3.5-4 cm the sparkling gourami is one…
- 10 gal min
- Peaceful
- 24–28°C
-
Guppy (Fancy)
Sold as the bulletproof beginner fish, the guppy (Poecilia reticulata) is really two animals.
- 10 gal min
- Peaceful
- 22–28°C
-
Reticulated Hillstream Loach
Lift one off a shop rock and it reads less like a fish than a thumb-length stingray with a sucker for a belly: flat, fan-finned,…
- 30 gal min
- Peaceful
- 20–24°C
-
Green Severum
Aquarists call it the "poor man's discus", and the nickname earns its keep: the green severum wears the same tall, coin-round,…
- 55 gal min
- Semi-aggressive
- 24–29°C
-
Common Goldfish
A common goldfish is a coldwater pond animal in the costume of a throwaway pet.
- 75 gal min
- Peaceful
- 15–24°C
-
Mosquito Rasbora (Dwarf Rasbora)
Read the flank and you have read the name: a dark line runs the whole length of the body and stops in a round spot at the tail…
- 10 gal min
- Peaceful
- 23–28°C
-
Cherry Barb
Keep one cherry barb on its own and you will wonder what the fuss is about — a drab tan fish skulking in a corner.
- 15 gal min
- Peaceful
- 23–27°C
-
Salt and Pepper Corydoras
Watch a settled group and you will catch this checkerboard dwarf doing something its family almost never does: at barely 3 cm it…
- 10 gal min
- Peaceful
- 20–26°C
-
Three-spot (Blue/Opaline/Gold) Gourami
Count the dark spots along its side and you find only two — the famous "third" is just the eye, drafted in to make the name work.
- 30 gal min
- Semi-aggressive
- 22–28°C
-
Dojo Loach (Weather Loach)
Drop the barometric pressure ahead of a storm and a dojo loach erupts — swimming frantically up the glass, sometimes standing on…
- 55 gal min
- Peaceful
- 16–24°C
-
Clown Loach
Sold cheap as a 5 cm juvenile, the clown loach is one of the hobby's most mis-sold animals: that bargain little fish becomes a…
- 125 gal min
- Peaceful
- 25–30°C
-
White Cloud Mountain Minnow
A thin line of green-gold light runs flank to tail, capped at each end by red-tipped, white-edged fins — the livery that earned…
- 15 gal min
- Peaceful
- 14–22°C
-
Diamond Tetra
Buy the dull one and wait — the diamonds come with age.
- 20 gal min
- Semi-aggressive
- 24–28°C
-
Rubber Lip Pleco
That broad, fleshy lower lip is the whole sales pitch: a suckermouth built for rasping, and unlike most plecos sold as "algae…
- 25 gal min
- Peaceful
- 21–26°C
-
Buenos Aires Tetra
Drop a Buenos Aires tetra into a lush planted tank and within weeks it grazes the soft plants down to bare stems — that…
- 30 gal min
- Semi-aggressive
- 18–28°C
-
Tiger Barb
Reputation precedes the tiger barb: the hobby's most infamous fin-nipper, blamed for shredded bettas and stressed angelfish…
- 20 gal min
- Semi-aggressive
- 20–26°C
-
Giant Danio
Ten to twelve centimetres of blue-and-gold muscle, the giant danio is a near-tireless open-water sprinter that patrols the upper…
- 30 gal min
- Semi-aggressive
- 22–26°C
-
Green Neon (Kubotai) Rasbora
Drop a shoal of Microdevario kubotai over dark sand and the tank glows lime-green — a colour you almost never see at this size,…
- 10 gal min
- Peaceful
- 20–27°C
-
Nerite Snail
The nerite is the hobby's best algae-eating snail and the snail that, by biology rather than luck, will never overrun your tank…
- 5 gal min
- Peaceful
- 22–27°C
-
Kribensis (Rainbow Krib)
Here the female is the show-off.
- 20 gal min
- Territorial
- 24–27°C
-
Zebra Danio
Two worlds claim the zebra danio.
- 10 gal min
- Peaceful
- 18–25°C
-
Bristlenose Pleco
A mature male bristlenose wears a crown of branching, antler-like tentacles across his snout — the fleshy "bristles" that name…
- 30 gal min
- Peaceful
- 23–27°C
-
Licorice Gourami
A male licorice gourami in true blackwater is a thumbnail-sized flash of electric blue and red, flaring barred fins in a…
- 10 gal min
- Peaceful
- 22–28°C
-
Asian Stone Catfish
Here is a catfish that disguises itself as a stone.
- 10 gal min
- Peaceful
- 18–24°C
-
Flame Tetra (Von Rio Tetra)
Watch where the colour sits: the front half stays plain silver, then the rear half ignites into flame-red and orange, brightest…
- 15 gal min
- Peaceful
- 22–28°C
-
Honey Gourami
Beginners reach for the dwarf gourami's colour and keep losing it within months to an incurable virus.
- 10 gal min
- Peaceful
- 23–28°C
-
Betta (Siamese Fighting Fish)
A betta is a tropical, air-breathing fish bred over centuries from the fighting fish of Thailand's rice paddies — beautiful,…
- 5 gal min
- Territorial
- 24–28°C
-
Pearl Danio
Catch a pearl danio in good light and the name explains itself: the body throws a mother-of-pearl sheen of violet and pink,…
- 20 gal min
- Peaceful
- 16–25°C
-
Harlequin Rasbora
Wearing a black wedge shaped like the diamond on a harlequin jester's costume, Trigonostigma heteromorpha is the fish that set…
- 15 gal min
- Peaceful
- 21–28°C
-
Dwarf Pencilfish
Slender as its name, it wears three dark stripes drawn the length of each pale-gold flank — until lights-out, when those stripes…
- 10 gal min
- Peaceful
- 22–28°C
-
Kuhli Loach
Half worm, half fish, the kuhli loach spends daylight buried in sand or wedged under wood and only uncoils at dusk to sift the…
- 20 gal min
- Peaceful
- 24–30°C
-
Rummynose Tetra
The rummynose tetra is the tightest-schooling fish in the common hobby — a silver torpedo with a blazing red nose and a…
- 20 gal min
- Peaceful
- 24–27°C
-
Julii Corydoras
Here is the headline that should change how you read every cory label: the fish sold as the "julii cory" is almost never the…
- 20 gal min
- Peaceful
- 22–26°C
-
Emperor Tetra
A black line set inside a stripe that runs green to blue to violet down the flank, a male whose eye glows metallic blue, and a…
- 20 gal min
- Peaceful
- 23–27°C
-
Pictus Catfish
Watch a pictus catfish for a minute and it breaks the catfish mould: instead of parking on the bottom, this silver,…
- 55 gal min
- Predatory
- 23–27°C
-
Oscar
The shop-cup juvenile looks manageable; the adult is not.
- 100 gal min
- Predatory
- 23–28°C
-
Dwarf Gourami
The dwarf gourami is the beautiful beginner fish with a dark secret: a large share of mass-bred stock carries an incurable…
- 10 gal min
- Peaceful
- 25–28°C
-
Bamboo Shrimp (Wood/Fan Shrimp)
Watch a bamboo shrimp settle on a rock and open its feathery front fans into the current and you have seen the whole animal: a…
- 20 gal min
- Peaceful
- 20–27°C
-
Black Skirt Tetra
That broad black 'skirt' — a flared anal fin sweeping back beneath a tall dark dorsal, set off by two crisp bars behind the…
- 20 gal min
- Semi-aggressive
- 20–26°C
-
Amano Shrimp
Amano shrimp are the hobby's best algae-eating shrimp — specialists for hair and thread algae and one of the few common cleanup…
- 10 gal min
- Peaceful
- 18–27°C
-
Rosy Red Minnow (Fathead Minnow)
Scooped from a feeder tank by the dozen for pennies, the rosy red is the gold-orange form of the North American fathead minnow —…
- 20 gal min
- Peaceful
- 10–24°C
-
Gold Barb
Buy a "gold barb" and you are buying a colour that does not exist in the wild: the natural Chinese barb is a green-bronze fish,…
- 20 gal min
- Peaceful
- 18–26°C
-
Scissortail Rasbora
Watch the tail.
- 30 gal min
- Peaceful
- 22–28°C
-
Electric Blue Acara
Most cichlids earn the family's reputation for aggression; this one quietly disproves it.
- 30 gal min
- Semi-aggressive
- 22–28°C
-
Celebes Rainbowfish
Buy soft, acidic blackwater for your tetras, drop a Celebes rainbowfish into it, and watch it fade — because this is the rare…
- 20 gal min
- Peaceful
- 22–28°C
-
Medaka Ricefish (Japanese Ricefish)
Drain a Japanese rice paddy in autumn and the medaka is the fish still flicking through the cold mud — a tough little ricefish…
- 10 gal min
- Peaceful
- 16–26°C
-
Assassin Snail
You buy an assassin snail to eat your other snails — it is a carnivore that hunts down bladder, pond, ramshorn and trumpet pests…
- 5 gal min
- Peaceful
- 18–25°C
-
Jewel Cichlid
Gorgeous, and a terror - that tension is the whole fish.
- 30 gal min
- Aggressive
- 23–27°C
-
Cherry Shrimp
Cherry shrimp are the one shrimp a beginner can actually breed.
- 5 gal min
- Peaceful
- 18–28°C
-
Banded Gourami
Trichogaster fasciata is the heavyweight of the small gouramis: at roughly 10 cm - males to about 12 cm - it dwarfs the honey…
- 20 gal min
- Semi-aggressive
- 21–28°C
-
Golden Wonder Killifish (Striped Panchax)
Strip away the metallic gold and you have Aplocheilus lineatus, the striped panchax — a line-bred colour form, not a separate…
- 20 gal min
- Predatory
- 22–26°C
-
Kissing Gourami
The kiss is a fight.
- 75 gal min
- Semi-aggressive
- 22–30°C
-
Keyhole Cichlid
Most cichlids are chosen for swagger; the keyhole is chosen for the opposite.
- 30 gal min
- Peaceful
- 22–28°C
-
Endler's Livebearer
A male Endler's livebearer is barely an inch of fish carrying some of the most intense metallic colour in fresh water — electric…
- 10 gal min
- Peaceful
- 22–28°C
-
Peaceful Betta (Crescent Betta)
Here is the line that sets this betta apart from all the rest: you can sometimes keep more than one.
- 10 gal min
- Semi-aggressive
- 21–28°C
-
Platy
Start your livebearers with a platy and you have picked the easiest fish in the group — hardy, endlessly colourful, and so…
- 10 gal min
- Peaceful
- 20–26°C
-
Clown Killifish
Look first at the male's tail: a candy-striped torpedo flare of fire-orange, electric blue and white that earns this 3.5 cm…
- 5 gal min
- Peaceful
- 20–26°C
-
Swordtail
That long lower lobe trailing off a male's tail — the "sword" the fish is named for — is a piece of evolutionary theatre: female…
- 20 gal min
- Peaceful
- 22–28°C
-
Cockatoo Dwarf Cichlid (Apisto Cacatuoides)
Male cacatuoides flare the spiky, raised first-dorsal rays that give the fish its name — a living cockatoo crest worn over a…
- 20 gal min
- Territorial
- 24–29°C
-
Upside-Down Catfish
Most fish are dark above and pale below; the upside-down catfish is painted the other way round, and that single reversal…
- 30 gal min
- Peaceful
- 23–28°C
-
Pearl Gourami
Give a pearl gourami a calm, dim, heavily planted tank and it earns its 'lace' and 'mosaic' nicknames — a silvery body dusted…
- 30 gal min
- Peaceful
- 24–28°C
-
Checker Barb
Run your eye down a checker barb's flank and you can read its name straight off the fish: a dark spot sits on each large scale,…
- 20 gal min
- Peaceful
- 20–25°C
-
Bala Shark
Bright silver, torpedo-bodied, every fin dipped in black — the bala shark is one of the prettiest fish a beginner can ruin, and…
- 150 gal min
- Semi-aggressive
- 22–28°C
-
Neon Dwarf Rainbowfish
Praecox is Latin for 'precocious', and that is the whole pitch: this fish locks in the deep, adult body of a rainbowfish while…
- 20 gal min
- Peaceful
- 23–27°C
-
Tinfoil Barb
Those mirror-bright, foil-silver flanks and the red-edged, black-tipped fins are the whole sales pitch — and the whole trap.
- 150 gal min
- Semi-aggressive
- 22–28°C
-
Redtail Black Shark
Jet-black from snout to tail save for one blood-red caudal fin, the redtail black shark wears the most uncompromising livery of…
- 55 gal min
- Aggressive
- 22–27°C
-
Siamese Algae Eater
The Siamese algae eater is the genuine article for black-beard and hair algae — one of the very few aquarium fish that actually…
- 50 gal min
- Semi-aggressive
- 22–26°C
-
Dwarf Emerald Rasbora
Count the emerald bars laddered down its copper flanks: a dozen or so vertical turquoise stripes are the quickest way to tell…
- 10 gal min
- Peaceful
- 20–24°C
-
Glass Catfish
Hold one up to the light and you look straight through it: the run of the spine, a beating heart, and a single silver sac of…
- 30 gal min
- Peaceful
- 20–26°C
-
Freshwater Angelfish
Sold as a serene centrepiece for a peaceful community tank, the freshwater angelfish (Pterophyllum scalare) is really a tall…
- 29 gal min
- Semi-aggressive
- 24–30°C
-
Celestial Pearl Danio
Discovered only in 2006 and sold at first as the 'galaxy rasbora', the celestial pearl danio was falsely reported nearly extinct…
- 10 gal min
- Peaceful
- 20–26°C
-
Multifasciatus Shell-Dweller
This is the smallest cichlid in the world, and it lives inside a snail shell.
- 10 gal min
- Territorial
- 24–27°C
-
Rainbow Shark
Buy a rainbow shark and you really get two fish: the calm, almost-shy two-inch juvenile in the shop tank, and the six-inch,…
- 50 gal min
- Aggressive
- 22–27°C
-
Panda Corydoras
Two patches of black — a bandit's mask across the eyes and a second blot at the base of the tail — sit on a pinkish-white body…
- 20 gal min
- Peaceful
- 20–25°C
-
Five-banded Barb
It wears the bold vertical bars of a tiger barb, so shops sell it on the resemblance — but the five-banded barb is that famous…
- 20 gal min
- Peaceful
- 23–28°C
-
Black Neon Tetra
Despite the name, this is not a neon — and it is not a colour form of one.
- 20 gal min
- Peaceful
- 23–27°C
-
Moonlight Gourami
Tilt the tank light and the plain silver flanks throw a cool blue-green shimmer — the 'moonlight' that gives this gourami every…
- 30 gal min
- Peaceful
- 25–30°C
-
Bolivian Ram
Almost every dwarf cichlid comes with a warning label.
- 20 gal min
- Peaceful
- 24–27°C
-
Boesemani Rainbowfish
The fish in the catalogue photo — a steel-blue front half meeting a blazing orange-red rear, split almost as cleanly as if…
- 30 gal min
- Peaceful
- 24–28°C
-
Serpae Tetra
Blood-red flanks, a black comma-shaped blotch stamped behind the gill cover, and a black-tipped dorsal fin make the serpae tetra…
- 20 gal min
- Semi-aggressive
- 20–28°C
-
Ember Tetra
The ember tetra is a living coal — a translucent, orange-to-red nano tetra barely two centimetres long that only lights up in a…
- 10 gal min
- Peaceful
- 20–28°C
-
Common Pleco
That 7–10 cm bargain "algae eater" in the shop tank is a giant in disguise.
- 125 gal min
- Semi-aggressive
- 22–30°C
-
Bronze Corydoras
Few community fish forgive a beginner's mistakes like the bronze corydoras.
- 20 gal min
- Peaceful
- 22–26°C
-
Discus
Get the water right and the discus rewards you like nothing else in freshwater — a hand-sized living disc, as tall as it is…
- 75 gal min
- Peaceful
- 28–30°C
-
Bleeding Heart Tetra
That single crimson splash over the heart — on a tall, diamond-deep, rosy-silver body — is exactly where the name comes from,…
- 30 gal min
- Peaceful
- 21–28°C
-
Black Phantom Tetra
Find the smoky charcoal blotch behind the gill cover, ringed in a faint halo of iridescent grey — that "phantom" shoulder mark…
- 20 gal min
- Peaceful
- 20–28°C
-
Zebra Loach
Count the stripes: where a yoyo or clown loach wears a handful of bold bars, the zebra loach is wrapped head to tail in dozens…
- 30 gal min
- Peaceful
- 23–26°C
-
Croaking Gourami
Two male croaking gouramis settle their quarrels out loud, by talking rather than biting: they circle head-to-tail, flare their…
- 15 gal min
- Peaceful
- 22–28°C
Fish encyclopedia
Browse the freshwater fish encyclopedia
Care guides for 126+ freshwater species, grouped by type — each one sourced, dated (v2026.06) and welfare-checked, not generic. See the full 126-species list →
Catfish & loaches
Gouramis & bettas
Rasboras & danios
Shrimp & snails
Coldwater
Compatibility
Popular "can they live together?" questions
The pairings aquarists ask about most — each answered with the welfare engine's verdict and the reasons behind it.
Every fish guide lists more compatible mates, and the planner checks any combination live.
Why TankStocking
A stocking calculator built around fish welfare
🌱 Planted-tank aware
The old tools flag a healthy planted tank as "overstocked". TankStocking doesn't make that mistake — without ever relaxing the checks that actually protect fish.
🛟 Welfare-first, not a single %
A clear verdict — Good / Caution / Not recommended — with the specific reasons listed. Tank too small, school too small, temperature clash, aggression, fin-nipping, predation.
🔍 Transparent & sourced
Every species figure is sourced and dated (v2026.06). We publish the full model — no black box.
📱 Fast & shareable
Works instantly on your phone. One tap copies a share link or a forum-ready summary of your build.
Popular tank sizes
Not sure where to start? Pick your tank size for stocking ideas and a planner pre-set to that volume.
Or browse the full freshwater community fish list (126 sourced species) and per-fish tank-mate guides.
Frequently asked
Is TankStocking free?
Yes — every tool is free and works in your browser with no account or sign-up.
How is this different from AqAdvisor?
TankStocking is built for modern phones and browsers, accounts for planted tanks instead of flagging them as overstocked, leads with clear welfare warnings rather than a single percentage, and publishes exactly how it works with dated, sourced species data. See the full TankStocking vs AqAdvisor comparison.
Does it cover saltwater or reef tanks?
Not yet — TankStocking focuses on doing freshwater really well. A reef/saltwater mode is on the roadmap.
Will the planner tell me my fish are 100% safe?
No tool can promise that. TankStocking gives a conservative planning estimate and flags risks; you still need to cycle the tank, test your water, and observe your fish.
Plan it before you buy it.
Sixty seconds in the planner can save a fish's life and your money.