Aquarium Stocking Calculator

Add your tank and the fish you're considering. TankStocking checks compatibility, schooling needs, temperature, aggression and bio-load, and tells you — honestly — whether it will work.

Your tank

no size set

Pick a common size, or enter your own dimensions.

Inside dimensions

Length

Width

Height

Volume

Heavily planted, mature tank

Add fish & invertebrates

Search 126 freshwater species by name or group.

Verdict

How to read your verdict

The planner gives one of four verdicts, with the reasons spelled out:

Good starter plan — no welfare checks failed. Still cycle the tank and verify your water.
Worth a closer look — workable, but something needs attention (a small school, a tight bio-load, mixed temperature preferences).
Not recommended as-is — a serious problem would harm the fish: a tank too small, a temperature clash, or a predator with bite-size tankmates.
Unassessed — we don't have data for a species you added, so we won't guess.

The stocking-level gauge is a rough estimate weighted by adult size and waste output — a guide, never the final word. The welfare checks are what protect your fish.

All 126 freshwater species in TankStocking

Sizes and minimums are sourced from reputable care references (v2026.06). Search the same list inside the planner above.

Species	Group	Adult size	Min tank	Min group	Temperament	Temp
Amano Shrimp Caridina multidentata	Invertebrates	5 cm	10 gal	—	peaceful	18–27°C
Asian Stone Catfish Hara jerdoni	Plecos & Catfish	3.8 cm	10 gal	—	peaceful · advanced	18–24°C
Assassin Snail Clea helena (Anentome helena)	Invertebrates	2 cm	5 gal	—	peaceful	18–25°C
Bala Shark Balantiocheilos melanopterus	Barbs	35 cm	150 gal	4+	semi-aggressive · advanced	22–28°C
Bamboo Shrimp (Wood/Fan Shrimp) Atyopsis moluccensis	Invertebrates	10 cm	20 gal	—	peaceful	20–27°C
Banded Gourami Trichogaster fasciata	Anabantoids (Bettas/Gouramis)	10 cm	20 gal	—	semi-aggressive	21–28°C
Betta (Siamese Fighting Fish) Betta splendens	Anabantoids (Bettas/Gouramis)	6.5 cm	5 gal	—	territorial	24–28°C
Black Neon Tetra Hyphessobrycon herbertaxelrodi	Tetras	3.5 cm	20 gal	6+	peaceful	23–27°C
Black Phantom Tetra Hyphessobrycon megalopterus	Tetras	3.6 cm	20 gal	6+	peaceful	20–28°C
Black Skirt Tetra Gymnocorymbus ternetzi	Tetras	6 cm	20 gal	6+	semi-aggressive · fin-nipper	20–26°C
Bleeding Heart Tetra Hyphessobrycon erythrostigma	Tetras	6 cm	30 gal	8+	peaceful	21–28°C
Boesemani Rainbowfish Melanotaenia boesemani	Rainbowfish	10 cm	30 gal	6+	peaceful	24–28°C
Bolivian Ram Mikrogeophagus altispinosus	Cichlids	8 cm	20 gal	—	peaceful	24–27°C
Brilliant Rasbora Rasbora einthovenii	Rasboras	9 cm	29 gal	6+	peaceful	22–26°C
Bristlenose Pleco Ancistrus sp.	Plecos & Catfish	13 cm	30 gal	—	peaceful	23–27°C
Bronze Corydoras Corydoras aeneus	Corydoras	7 cm	20 gal	6+	peaceful	22–26°C
Buenos Aires Tetra Hyphessobrycon anisitsi	Tetras	7 cm	30 gal	6+	semi-aggressive · fin-nipper	18–28°C
Bumblebee Goby Brachygobius doriae	Oddball	3.5 cm	10 gal	—	territorial · advanced	22–28°C
Cardinal Tetra Paracheirodon axelrodi	Tetras	3 cm	15 gal	6+	peaceful	23–29°C
Celebes Rainbowfish Marosatherina ladigesi	Rainbowfish	8 cm	20 gal	6+	peaceful	22–28°C
Celestial Pearl Danio Celestichthys margaritatus	Danios	2.1 cm	10 gal	8+	peaceful	20–26°C
Checker Barb Oliotius oligolepis	Barbs	5 cm	20 gal	6+	peaceful	20–25°C
Cherry Barb Puntius titteya	Barbs	5 cm	15 gal	6+	peaceful	23–27°C
Cherry Shrimp Neocaridina davidi	Invertebrates	3 cm	5 gal	—	peaceful	18–28°C
Chili Rasbora Boraras brigittae	Rasboras	2 cm	5 gal	8+	peaceful	20–28°C
Chocolate Gourami Sphaerichthys osphromenoides	Anabantoids (Bettas/Gouramis)	5 cm	15 gal	6+	peaceful · advanced	26–31°C
Clown Killifish Epiplatys annulatus	Killifish	3.5 cm	5 gal	6+	peaceful	20–26°C
Clown Loach Chromobotia macracanthus	Loaches	30 cm	125 gal	5+	peaceful · advanced	25–30°C
Clown Pleco Panaqolus maccus	Plecos & Catfish	9 cm	20 gal	—	peaceful	23–28°C
Cockatoo Dwarf Cichlid (Apisto Cacatuoides) Apistogramma cacatuoides	Cichlids	8 cm	20 gal	—	territorial	24–29°C
Common Goldfish Carassius auratus	Coldwater	30 cm	75 gal	—	peaceful · advanced	15–24°C
Common Pleco Pterygoplichthys pardalis	Plecos & Catfish	45 cm	125 gal	—	semi-aggressive · advanced	22–30°C
Congo Tetra Phenacogrammus interruptus	Tetras	8 cm	30 gal	6+	peaceful	23–28°C
Convict Cichlid Amatitlania nigrofasciata	Cichlids	12 cm	40 gal	—	aggressive	24–28°C
Croaking Gourami Trichopsis vittata	Anabantoids (Bettas/Gouramis)	7 cm	15 gal	—	peaceful	22–28°C
Denison Barb (Roseline Shark) Sahyadria denisonii	Barbs	15 cm	55 gal	6+	semi-aggressive · fin-nipper · advanced	20–25°C
Diamond Tetra Moenkhausia pittieri	Tetras	6 cm	20 gal	6+	semi-aggressive · fin-nipper	24–28°C
Discus Symphysodon aequifasciatus	Cichlids	20 cm	55 gal	5+	peaceful · advanced	28–30°C
Dojo Loach (Weather Loach) Misgurnus anguillicaudatus	Loaches	25 cm	55 gal	—	peaceful · advanced	16–24°C
Dwarf Chain Loach Ambastaia sidthimunki	Loaches	6 cm	20 gal	6+	peaceful	24–28°C
Dwarf Emerald Rasbora Celestichthys erythromicron	Danios	2 cm	10 gal	8+	peaceful	20–24°C
Dwarf Gourami Trichogaster lalius	Anabantoids (Bettas/Gouramis)	8.5 cm	10 gal	—	peaceful	25–28°C
Dwarf Pencilfish Nannostomus marginatus	Tetras	2.5 cm	10 gal	8+	peaceful	22–28°C
Dwarf Pufferfish (Pea Puffer) Carinotetraodon travancoricus	Oddball	2.5 cm	5 gal	—	semi-aggressive · fin-nipper	22–28°C
Electric Blue Acara Andinoacara pulcher	Cichlids	16 cm	30 gal	—	semi-aggressive	22–28°C
Ember Tetra Hyphessobrycon amandae	Tetras	2 cm	10 gal	6+	peaceful	20–28°C
Emperor Tetra Nematobrycon palmeri	Tetras	4.2 cm	20 gal	6+	peaceful · fin-nipper	23–27°C
Endler's Livebearer Poecilia wingei	Livebearers	3 cm	10 gal	—	peaceful	22–28°C
Fancy Goldfish Carassius auratus	Coldwater	20 cm	30 gal	—	peaceful · advanced	18–23°C
Firemouth Cichlid Thorichthys meeki	Cichlids	15 cm	30 gal	—	territorial	23–29°C
Five-banded Barb Desmopuntius pentazona	Barbs	5 cm	20 gal	8+	peaceful	23–28°C
Flame Tetra (Von Rio Tetra) Hyphessobrycon flammeus	Tetras	4 cm	15 gal	6+	peaceful	22–28°C
Freshwater Angelfish Pterophyllum scalare	Cichlids	15 cm	29 gal	—	semi-aggressive	24–30°C
German Blue Ram Mikrogeophagus ramirezi	Cichlids	5 cm	20 gal	—	peaceful · advanced	27–30°C
Ghost Shrimp (Glass/Grass Shrimp) Palaemonetes paludosus	Invertebrates	4 cm	5 gal	—	peaceful	18–28°C
Giant Danio Devario aequipinnatus	Danios	12 cm	30 gal	6+	semi-aggressive · fin-nipper	22–26°C
Glass Catfish Kryptopterus vitreolus	Plecos & Catfish	6.5 cm	30 gal	6+	peaceful · advanced	20–26°C
Glowlight Tetra Hemigrammus erythrozonus	Tetras	4 cm	15 gal	6+	peaceful	24–28°C
Gold Barb Barbodes semifasciolatus	Barbs	8 cm	20 gal	6+	peaceful	18–26°C
Gold White Cloud Mountain Minnow Tanichthys albonubes (gold form)	Coldwater	4 cm	15 gal	8+	peaceful	14–22°C
Golden Wonder Killifish (Striped Panchax) Aplocheilus lineatus	Killifish	10 cm	20 gal	—	predatory	22–26°C
Green Neon (Kubotai) Rasbora Microdevario kubotai	Rasboras	2 cm	10 gal	8+	peaceful	20–27°C
Green Severum Heros efasciatus	Cichlids	30 cm	55 gal	—	semi-aggressive	24–29°C
Guppy (Fancy) Poecilia reticulata	Livebearers	5 cm	10 gal	—	peaceful	22–28°C
Harlequin Rasbora Trigonostigma heteromorpha	Rasboras	4.5 cm	15 gal	8+	peaceful	21–28°C
Honey Gourami Trichogaster chuna	Anabantoids (Bettas/Gouramis)	5 cm	10 gal	—	peaceful	23–28°C
Jewel Cichlid Hemichromis bimaculatus	Cichlids	14 cm	30 gal	—	aggressive	23–27°C
Julii Corydoras Corydoras trilineatus	Corydoras	6 cm	20 gal	6+	peaceful	22–26°C
Keyhole Cichlid Cleithracara maronii	Cichlids	11 cm	30 gal	—	peaceful	22–28°C
Kissing Gourami Helostoma temminkii	Anabantoids (Bettas/Gouramis)	25 cm	75 gal	—	semi-aggressive · advanced	22–30°C
Kribensis (Rainbow Krib) Pelvicachromis pulcher	Cichlids	9 cm	20 gal	—	territorial	24–27°C
Kuhli Loach Pangio kuhlii	Loaches	9 cm	20 gal	5+	peaceful	24–30°C
Lambchop Rasbora Trigonostigma espei	Rasboras	3 cm	10 gal	8+	peaceful	23–28°C
Least Killifish (Dwarf Livebearer) Heterandria formosa	Livebearers	3.5 cm	5 gal	—	peaceful	16–24°C
Lemon Tetra Hyphessobrycon pulchripinnis	Tetras	4 cm	20 gal	6+	peaceful	20–28°C
Licorice Gourami Parosphromenus deissneri	Anabantoids (Bettas/Gouramis)	4 cm	10 gal	—	peaceful · advanced	22–28°C
Marbled Hatchetfish Carnegiella strigata	Tetras	4 cm	20 gal	6+	peaceful · advanced	24–28°C
Medaka Ricefish (Japanese Ricefish) Oryzias latipes	Killifish	3.5 cm	10 gal	6+	peaceful	16–26°C
Molly (Common / Sailfin) Poecilia sphenops / Poecilia latipinna	Livebearers	12 cm	20 gal	—	peaceful	24–28°C
Moonlight Gourami Trichopodus microlepis	Anabantoids (Bettas/Gouramis)	15 cm	30 gal	—	peaceful	25–30°C
Mosquito Rasbora (Dwarf Rasbora) Boraras maculatus	Rasboras	2.5 cm	10 gal	8+	peaceful	23–28°C
Multifasciatus Shell-Dweller Neolamprologus multifasciatus	Cichlids	4 cm	10 gal	—	territorial	24–27°C
Mystery Snail Pomacea bridgesii	Invertebrates	5 cm	10 gal	—	peaceful	20–28°C
Neon Dwarf Rainbowfish Melanotaenia praecox	Rainbowfish	7 cm	20 gal	6+	peaceful	23–27°C
Neon Tetra Paracheirodon innesi	Tetras	3 cm	10 gal	6+	peaceful	21–25°C
Nerite Snail Neritina/Vittina spp.	Invertebrates	2.5 cm	5 gal	—	peaceful	22–27°C
Odessa Barb Pethia padamya	Barbs	8 cm	20 gal	6+	semi-aggressive · fin-nipper	16–26°C
Oscar Astronotus ocellatus	Cichlids	35 cm	75 gal	—	predatory · advanced	23–28°C
Otocinclus Otocinclus macrospilus	Plecos & Catfish	4 cm	10 gal	6+	peaceful · advanced	20–26°C
Panda Corydoras Corydoras panda	Corydoras	5 cm	20 gal	6+	peaceful	20–25°C
Paradise Fish Macropodus opercularis	Anabantoids (Bettas/Gouramis)	8 cm	20 gal	—	aggressive · fin-nipper · advanced	16–26°C
Peaceful Betta (Crescent Betta) Betta imbellis	Anabantoids (Bettas/Gouramis)	6 cm	10 gal	—	semi-aggressive	21–28°C
Peacock Gudgeon Tateurndina ocellicauda	Oddball	7.5 cm	15 gal	—	peaceful	22–26°C
Pearl Danio Danio albolineatus	Danios	5.5 cm	20 gal	8+	peaceful	16–25°C
Pearl Gourami Trichopodus leerii	Anabantoids (Bettas/Gouramis)	12 cm	30 gal	—	peaceful	24–28°C
Peppered Corydoras Corydoras paleatus	Corydoras	7 cm	20 gal	6+	peaceful	18–24°C
Pictus Catfish Pimelodus pictus	Plecos & Catfish	12.7 cm	55 gal	—	predatory · advanced	23–27°C
Platy Xiphophorus maculatus	Livebearers	6 cm	10 gal	—	peaceful	20–26°C
Pygmy Corydoras Corydoras pygmaeus	Corydoras	3 cm	10 gal	6+	peaceful	22–26°C
Rainbow Shark Epalzeorhynchos frenatum	Loaches	15 cm	50 gal	—	aggressive · fin-nipper · advanced	22–27°C
Redtail Black Shark Epalzeorhynchos bicolor	Loaches	15 cm	55 gal	—	aggressive · fin-nipper · advanced	22–27°C
Reticulated Hillstream Loach Sewellia lineolata	Loaches	7 cm	30 gal	—	peaceful · advanced	20–24°C
Rosy Barb Pethia conchonius	Barbs	14 cm	30 gal	6+	semi-aggressive · fin-nipper	18–24°C
Rosy Red Minnow (Fathead Minnow) Pimephales promelas	Coldwater	7 cm	20 gal	6+	peaceful · fin-nipper	10–24°C
Rubber Lip Pleco Chaetostoma formosae	Plecos & Catfish	12 cm	25 gal	—	peaceful	21–26°C
Rummynose Tetra Hemigrammus rhodostomus	Tetras	5 cm	20 gal	6+	peaceful	24–27°C
Salt and Pepper Corydoras Corydoras habrosus	Corydoras	3.5 cm	10 gal	6+	peaceful	20–26°C
Scarlet Badis Dario dario	Oddball	2 cm	10 gal	—	peaceful	22–26°C
Scissortail Rasbora Rasbora trilineata	Rasboras	15 cm	30 gal	6+	peaceful	22–28°C
Serpae Tetra Hyphessobrycon eques	Tetras	4 cm	20 gal	6+	semi-aggressive · fin-nipper	20–28°C
Siamese Algae Eater Crossocheilus oblongus	Loaches	15 cm	30 gal	—	semi-aggressive	22–26°C
Silvertip Tetra Hasemania nana	Tetras	5 cm	20 gal	6+	semi-aggressive · fin-nipper	23–28°C
Snakeskin Gourami Trichopodus pectoralis	Anabantoids (Bettas/Gouramis)	25 cm	55 gal	—	peaceful · advanced	22–30°C
Sparkling (Pygmy) Gourami Trichopsis pumila	Anabantoids (Bettas/Gouramis)	4 cm	10 gal	—	peaceful	24–28°C
Sterbai Corydoras Corydoras sterbai	Corydoras	6.5 cm	20 gal	6+	peaceful	24–28°C
Swordtail Xiphophorus hellerii	Livebearers	12 cm	20 gal	—	peaceful	22–28°C
Threadfin Rainbowfish Iriatherina werneri	Rainbowfish	4 cm	15 gal	6+	peaceful · advanced	22–30°C
Three-spot (Blue/Opaline/Gold) Gourami Trichopodus trichopterus	Anabantoids (Bettas/Gouramis)	13 cm	30 gal	—	semi-aggressive	22–28°C
Tiger Barb Puntigrus tetrazona	Barbs	7 cm	20 gal	6+	semi-aggressive · fin-nipper	20–26°C
Tinfoil Barb Barbonymus schwanenfeldii	Barbs	35 cm	150 gal	5+	semi-aggressive · advanced	22–28°C
Upside-Down Catfish Synodontis nigriventris	Plecos & Catfish	9 cm	30 gal	4+	peaceful	23–28°C
White Cloud Mountain Minnow Tanichthys albonubes	Coldwater	4 cm	15 gal	8+	peaceful	14–22°C
X-ray (Pristella) Tetra Pristella maxillaris	Tetras	4.5 cm	15 gal	6+	peaceful	22–28°C
Yoyo Loach Botia almorhae	Loaches	15 cm	40 gal	5+	semi-aggressive	24–30°C
Zebra Danio Danio rerio	Danios	5 cm	10 gal	6+	peaceful · fin-nipper	18–25°C
Zebra Loach Botia striata	Loaches	9 cm	30 gal	5+	peaceful	23–26°C

Common questions

How does the stocking calculator work?

You set a tank size and add species. TankStocking then runs hard welfare checks (minimum tank size, schooling group minimums, temperature overlap, aggression, predation by size, and fin-nipping) and estimates a bio-load level. Any failed welfare check caps the verdict below "Good". See the methodology for the exact model.

Why doesn't it just give me a percentage?

A single "% stocked" number looks precise but hides what matters. A tank can be 50% "stocked" and still be wrong — a lone schooling fish, a predator with bite-size tankmates, or a temperature clash. TankStocking leads with a clear verdict and the specific reasons, and treats the stocking-level gauge as a rough estimate only.

Does it account for planted tanks?

Yes. Plants help process waste, so a heavily-planted, mature tank gets a small bio-load allowance. But plants never relax the welfare checks — they don't create swimming room, shrink an adult fish, or calm an aggressive one.

Can I share my plan?

Yes. Your whole build lives in the page URL, so copying the link shares the exact plan. There's also a one-tap "copy summary" for forum posts.

Is the result safe to follow blindly?

Treat it as a planning estimate, not a guarantee or veterinary advice. Always cycle a new tank, test your own water, add fish gradually, and watch how they actually behave.

TankStocking provides planning estimates, not veterinary advice. Living animals depend on a careful keeper — cycle your tank, test your water, and research every species. How this works →