Fish for a 10-Gallon Tank: 13 Species Sources Recommend

The short answer

Aqueon, LiveAquaria and TFH Magazine name guppies, platies, ember tetras, harlequin and chili rasboras, dwarf Corydoras, honey gouramis and bettas for tanks this size, and differ on zebra danios and neons. Aquarium Co-Op adds Endler’s, white clouds and celestial pearl danios. TFH suggests starting at “around one small fish per gallon”.

The figures come from Aqueon, an aquarium-products maker; LiveAquaria (LA), a live-fish retailer; Aquarium Co-Op (Co-Op), an aquarium retailer; hygger, an aquarium-equipment maker; and TFH Magazine, a fishkeeping magazine. Where they disagree, both are shown. All of it is for freshwater tanks. For general beginner advice, see our guide to aquarium fish for beginners.

The 13 Species at a Glance

Minimum tank and group size as each source states them.

Species	Minimum tank	Group size
Guppy	10 gal (LA); 5 gal for a trio (Co-Op)	3+, preferably 1 male to 2-3 females (Aqueon)
Endler’s livebearer	5-10 gal (Co-Op)	1 male, 2 females in 10 gal (Co-Op)
Platy	10 gal (LA)	3+ (Aqueon); a trio in 10 gal (Co-Op)
Zebra danio	10 gal (LA); TFH says no	6+ (Aqueon, Co-Op)
White cloud minnow	10 gal (Co-Op)	6+ (Co-Op)
Celestial pearl danio	10 gal (Co-Op)	6+; 10-15 go in 20 gal (Co-Op)
Neon tetra	10 gal (LA)	Aqueon: avoid, or 12+ with only corys or a bristlenose
Ember tetra	10 gal (LA); 5 gal (Co-Op)	6-10 (Co-Op)
Harlequin rasbora	10 gal (LA, Aqueon)	7+ (Aqueon); 8-10 (LA)
Chili rasbora	Kept in 3 gal planted (Co-Op); 3-10 gal for Boraras (Aqueon)	8-12 (Co-Op)
Pygmy cory	10 gal for a school (Co-Op)	8-12 (Co-Op)
Honey gourami	10 gal (Aqueon); 5-10 gal for one (Co-Op)	1; 3 do better in 20 gal (Co-Op)
Betta	4 gal alone (LA)	1 male (Aqueon)

For 5- to 10-gallon tanks, Aqueon’s tank-size guide says they “do not lend themselves to schools of fish”.

The Species, One by One

Guppy (Poecilia reticulata) and Endler’s Livebearer (Poecilia wingei)

Size and tank: LA lists the guppy at 2 in. Aqueon says guppies, platies and common mollies “will all do well in tanks under 10 gallons”. Co-Op says “a 10- or 20-gallon aquarium would be more appropriate in the long run” for guppies, because they breed quickly.
Water: Aqueon (most livebearers): 74-78°F, pH 7.0-8.4; LA’s guppy listing: 64-82°F, pH 5.5-8.0. For fancy guppies Co-Op says “An aquarium heater is recommended to keep the water warmer at 76 to 78°F”. It keeps Endler’s “at room temperature in an aquarium without a heater”. Aqueon warns: “if you have male and female livebearers, you will eventually have fry – plan accordingly!”

Platy (Xiphophorus maculatus)

Size: LA lists 2 in. Co-Op says “Most platy fish grow to 2-3 inches (5-7 cm)”, but “the dwarf platy only reaches a little over 1 inch”, and for 10 gallons recommends “a trio of teacup platys with one male and two females.”
Water: LA: 64-77°F, pH 7.0-8.2. Aqueon (most livebearers): 74-78°F, pH 7.0-8.4.

Zebra Danio (Danio rerio)

Sources differ. LA lists 3 in and a 10-gallon minimum. For 5- to 10-gallon tanks Aqueon says “Keeping a small group of these fish will add a lot of activity”. TFH disagrees: “Fish such as danios that need a lot of swimming space won’t be happy in 10 gallons.”
Water: LA: 64-75°F, pH 6.5-7.5. Aqueon (most danios): 70-78°F, pH 7.0-7.8.

White Cloud Mountain Minnow (Tanichthys albonubes)

Size and water: Co-Op describes “This 1.5-inch (4 cm) minnow”, gives “pH from 6.5-8.5 and temperatures from 65-77°F (18-25°C)” and says “They may get stressed if the water gets too warm but can readily live in a fish tank with no heater.” Aqueon groups white clouds with danios (70-78°F, pH 7.0-7.8).

Celestial Pearl Danio (Danio margaritatus)

Size and tank: Co-Op says “They grow up to 1 inch (2.5 cm) long” and: “We like keeping CPDs in at least 10 gallons of water, but if you purchase a bigger school of 10-15 fish as recommended, go for a 20-gallon aquarium or larger.”
Water: Co-Op’s care guide gives pH “6.6-8.0” and says “While they can live up to 78°F (26°C), they thrive in lower temperatures from 72-76°F (22-24°C).”

Neon Tetra (Paracheirodon innesi)

Sources differ. LA lists 1.5 in and “Extremely peaceful”. TFH says neons “are relatively inactive animals. This makes them a better choice for the small aquarium than similarly sized danios or minnows.” For 5- to 10-gallon tanks Aqueon advises to “avoid the more torpedo shaped tetras like neons and cardinals”, because “When only a few neons or cardinals mixed in with other species are kept in the tank, they do not display their best.” It adds: “If your heart is set on a school of neons, go for a minimum of 12 fish and do not keep any other fish in the tank other than some Corydoras or a bristlenose pleco.” Aqueon recommends the bristlenose itself in its 20- to 50-gallon section, and LA lists 30 gallons.
Water: LA’s listing: 68-78°F, pH 5.5-7.0. Aqueon (most tetras): 75-80°F, pH 6.8-7.8.

Ember Tetra (Hyphessobrycon amandae)

Size and tank: LA lists 1.25 in and “Diet: Omnivore”. Co-Op says it “only grows up to 0.8 inch (2 cm)”, so sources differ on size, and that “you have the flexibility to keep them in a 5-gallon nano tank with a smaller school”.
Water: LA’s listing: 72-77°F, pH 5.5-7.0. Co-Op: “pH of 5.5-7.5, 72-82°F (22-28°C)”. Aqueon (most tetras): 75-80°F, pH 6.8-7.8.

Harlequin Rasbora (Rasbora heteromorpha)

Size and tank: Aqueon says harlequins and similar rasboras “typically do not get larger than 2 inches” and are “good beginner fish for 10-gallon aquariums or larger.” LA lists 2 in.
Water: Aqueon (commercially raised rasboras): 75-80°F, pH 6.8-7.8. LA’s listing: 72-77°F, pH 6.0-6.5. Those two pH ranges do not overlap, though Aqueon adds: “Wild-caught fish prefer a pH of 5.0 to 7.0”.

Chili Rasbora (Boraras brigittae)

Size and tank: Co-Op says “They only grow to about ¾ inch (2 cm) long” and “we have successfully kept them in planted fish tanks as small as 3 gallons.” Aqueon says most of the smaller rasboras, including various Boraras species, “max out at 1 inch or less and are perfect inhabitants for desktop and nano aquariums of 3 to 10 gallons.”
Water and flow: Co-Op reports keeping them in “pH levels of 6.0-8.0, temperatures between 72-82°F (22-28°C)”. Aqueon says some rasboras, “especially members of the genus Boraras, are collected in the wild where the water is very soft and slightly acidic”. Co-Op says to “aim for a filter with low current like a sponge filter”, or to cover a hang-on-back or canister intake with a prefilter sponge “so the nano fish won’t accidentally get sucked up.”

Pygmy Cory and Other Dwarf Corydoras

Size and tank: Co-Op says the pygmy cory (Corydoras pygmaeus) “grows to a grand total of 1 inch (2.5 cm)”; “a small group could technically fit in a 5-gallon nano tank”, but it advises “a 10-gallon or larger aquarium so that you can keep a bigger school of at least 8-12 pygmies”. Aqueon: “A 30-gallon aquarium is best for most species, although pygmy Corys such as C. hastatus, C. habrosus and C. pygmaeus can be kept in smaller aquariums.”
Water: Co-Op gives the pygmy “pH of 6.4-7.5” and “72-78°F (22-26°C)”; Aqueon gives “pH between 7.0 and 8.0” and 74-80°F for “most captive bred Cory cats”.
Caution: Aqueon’s Corydoras guide: “Pristine water quality is essential to good health in these catfish. They should never be added to new aquariums or those that have been neglected.” Aqueon’s tank-size guide adds: “Like all bottom feeders, it is important to feed them directly and not just depend on them getting leftovers from feeding other fish.”

Honey Gourami (Trichogaster chuna)

Co-Op says it “stays around 2 inches (5 cm)”, that “A single honey gourami can live in a 5- or 10-gallon tank, but a group of three gouramis would do better in a 20-gallon aquarium”, and gives “pH of 6.0-8.0, temperatures between 74-82°F (23-28°C)”. Aqueon says “Sparkling, croaking, honey and dwarf gouramis can be kept in tanks as small as 10 gallons” and gives 75-80°F, pH 6.8-7.8 for most gouramis.

Betta (Betta splendens)

Tank: LA says a betta “should be kept singularly in aquariums of at least 4 gallons in size or with suitable, peaceful tank mates.” Aqueon: “Male bettas are highly territorial towards each other and must be kept separately or in a partitioned container. They can be kept with other fish in a peaceful community aquarium of 15 gallons or larger.” Co-Op says a betta with tank mates needs “at least 10 to 20 gallons with lots of cover and live plants”. Aqueon: “Avoid putting them with male gouramis, fin-nippers such as tiger barbs or active fish like giant danios.”
Water: Aqueon: 76-85°F, pH 6.8-7.5; LA: 75-86°F, pH 6.0-8.0. Aqueon: “bettas are jumpers, so keep a secure lid on the tank!” See our betta fish food roundup and our guide to reducing filter current.

How Many Fish Fit in 10 Gallons?

Each has its caveat:

TFH: “Initially, aim for around one small fish per gallon of water, adding them in small groups every couple of weeks. Once the aquarium is mature and your skills are honed, you should be able to keep two neon-tetra-size fish per gallon.” It says this “does rather depend on your fishkeeping skills and the quality of the filter.” For 10 gallons that is about 10 small fish to start and about 20 neon-size fish later (our arithmetic).
Co-Op: “In the past, it was often recommended to beginners that you can keep 1 inch of fish for every 1 gallon of water. This rule of thumb mainly applies to small community fish that are approximately 1-3 inches (2-7 cm) in size.” For a cycled tank it says “the easiest way to figure out how many fish you can add to an aquarium is by measuring the nitrate level and making sure it stays below 40 ppm”.
hygger: “Stock 1″ fish per gallon of the tank is a general fish stocking rule. However, it’s not universal; some species are territorial, aggressive, or have other limitations.”
Aqueon gives no total count. For 5- to 10-gallon tanks: “The bigger they are, the fewer you want to keep.” Also: “Don’t overstock your aquarium. Fish that are crowded may fight, and overstocking can lead to water quality problems.”

LA’s “schools of 8-10” harlequins at its 2-inch maximum come to 16-20 inches of fish, past the inch rule’s 10 inches for 10 gallons, while 8-10 fish is at or under TFH’s starting figure of about 10. Aqueon’s 12-neon minimum is above TFH’s start and under its mature figure of about 20 (all our arithmetic).

How fast to add them: sources differ. Aqueon: “Always test water before purchasing new fish, and only buy a few fish at a time. Wait at least a week between new fish additions.” Co-Op measures nitrate “each week for 2 to 3 weeks in a row” before the next species. Aqueon, a maker, says nitrate toxicity “varies depending on species, age and overall health, but levels above 50 ppm are undesirable in freshwater aquaria”, a different figure from Co-Op’s 40 ppm.

Combinations Sources Describe

Setup	Fish	Source
Centerpiece	1 gourami under 3 in: honey, or powder blue dwarf (“females are usually more peaceful than males”); 6-8 nano schooling fish; snails; 4-6 panda or 6-8 pygmy corys	Co-Op
Betta	1 male betta, 3-4 ember tetras or Boraras brigittae and a mystery snail, with hiding spots and a sponge filter (Aqueon: 15 gal)	hygger

Before the First Fish

Must-haves

A cycling plan

Co-Op explains why: in a newly set-up tank “there won’t be enough beneficial bacteria yet to process your fish’s waste and keep the water clean.” Sources describe two ways to cycle. API, a test-kit maker, says a “fishless cycle” “would require daily dosing of ammonia and bacteria to build the bacteria ecosystem prior to fish being acclimated to the aquarium”; in its “fish in cycle”, “it is recommended to add small amounts of fish at a time”. Our guide to cycling a fish tank gives the fishless and fish-in steps.

A filter sized for the tank

For 10 gallons TFH suggests “a filter with a turnover of 40 to 60 gallons per hour”.

A test kit

Aqueon: “Test the aquarium water for pH, ammonia and nitrite before adding new fish.” It says “The only safe ammonia level is zero” and “The only safe nitrite level is zero”. Our freshwater test kit roundup compares kits; for a reading above zero, see how to lower ammonia.

A water conditioner

Aqueon: “Always treat tap water with a water conditioner to neutralize chlorine and ammonia before adding it to the aquarium.” Our water conditioner roundup compares them.

A secure lid

Aqueon: “Keep a secure lid on the aquarium to prevent fish from jumping out if they feel scared or threatened.” See why fish jump.

Nice to have

Live plants. In Co-Op’s view, “A lush forest of actively growing aquatic plants is capable of absorbing large amounts of toxic waste”, with fast-growing stem and floating plants removing it fastest. No other source here ties plants to a stocking number.
A quarantine tank. See our guide to quarantining new fish.

What Changes the List

An unheated tank. Co-Op says white clouds and Endler’s can live without a heater, and that danios need none “As long as your room temperature at home stays between 67-80°F (19-27°C)”. Aqueon recommends a heater “If the aquarium is kept in a room below 74° F” for livebearers, 70° for danios and white clouds, 75° for tetras and rasboras.
Your tap water. Co-Op says guppies “enjoy pH levels at 7.0 or greater” and “like hard water”. LA’s neon and ember listings top out at pH 7.0, while Aqueon says “For most tetras, pH should be between 6.8 and 7.8”. Compare your tap water with each source’s range.

Where Sources Differ on 10 Gallons

Fish	One view	Other view
Panda cory	5-10 gal, “good choices” (Aqueon)	30 gal minimum (LA)
Kuhli loach	10 gal, groups of 4+ (TFH)	20 gal+ for 3-6 (Co-Op); 50 gal, black kuhli (LA)
Sparkling gourami	4-5 in 10 gal (TFH); 10 gal (Aqueon; LA text)	30 gal in LA’s stats
Bristlenose pleco	Named as the other tank mate for a 12+ neon school in 5-10 gal; recommended for 20-50 gal (Aqueon)	30 gal (LA); TFH: plecos too large for 10 gal
Dwarf gourami	10 gal (Aqueon); powder blue as a centerpiece (Co-Op)	TFH: “Dwarf gouramis Colisa lalia are best avoided, though. The males tend to be rather aggressive”

Ready to buy?

Our aquarium heater roundup sorts heaters by tank size; its 2- to 10-gallon preset is fixed at 78°F, so check your species’ range, and our fish tank filter roundup compares hang-on-back, canister and sponge filters.

Frequently Asked Questions

Q. What is the biggest fish for a 10-gallon tank?

No source names one. Aqueon says fish for 5- to 10-gallon tanks “should be small”, generally ½ to 2 inches at most. For its 10-gallon ideas Co-Op picks killifish that stay “3-4 inches (8-10 cm) or smaller”, kept in “a species-only tank”, and a gourami under 3 inches; the killifish is above Aqueon’s range, and the gourami may be. TFH says angelfish and plecos, as adults, “are simply too large for a 10-gallon tank.”

Q. Can goldfish live in a 10-gallon tank?

Aqueon says “Goldfish should never be kept in bowls, small aquariums or any unfiltered container!” Sources differ on size: Aqueon says adult common goldfish, comets and shubunkins “should have at least 20 gallons of water per fish, while adult fancy goldfish should have at least 10 gallons per adult fish.” Co-Op says for a fancy goldfish “a 20-gallon long aquarium is often recommended as the minimum tank size.” See why goldfish die in an aquarium.

Q. What else can live in a 10-gallon tank besides fish?

Co-Op suggests cherry shrimp (“start with 10 to 20 shrimp”; “for maximum survival rate, do not add any other species as tank mates”). TFH says nerite snails “hardly ever breed under aquarium conditions”, but “some of the species traded are brackish-water varieties, and these will not do well in freshwater aquaria.” See what aquarium snails eat.

Q. What should I do if a new fish looks sick?

Start with the ammonia and nitrite test above. For the fish itself, ask an aquatic veterinarian; disease and medication are outside what this site covers.

Sources (40)

Aquarium Tales Team

Written and reviewed by the Aquarium Tales Team. See the About page for how we work.