The short answer
Aquarium makers and fish retailers commonly recommend small, peaceful species for a first tank: guppies, platies, zebra danios, white cloud minnows, neon tetras, harlequin rasboras, cherry barbs, small Corydoras, bristlenose plecos and bettas. Choose by tank size and water. Sources describe two ways to cycle a new tank: fishless, or with a few fish at a time.
The figures come from Aqueon, an aquarium-products maker, and the species listings of LiveAquaria, a live-fish retailer, with Aquarium Co-Op, an aquarium retailer, for the white cloud minnow. Where they disagree, both are shown. All of it is for freshwater tanks.
The 10 Species at a Glance
Adult size and minimum tank are from LiveAquaria’s listings (white cloud: Aquarium Co-Op). Aqueon’s tank advice, where it differs, is in each entry below.
| Species | Max. adult size | Min. tank |
|---|---|---|
| Guppy | 2 in | 10 gal |
| Platy | 2 in | 10 gal |
| Zebra danio | 3 in | 10 gal |
| White cloud minnow | 1.5 in (Co-Op) | 10 gal (Co-Op) |
| Neon tetra | 1.5 in | 10 gal |
| Harlequin rasbora | 2 in | 10 gal |
| Cherry barb | 2 in | 20 gal |
| Panda cory | 2.5 in | 30 gal |
| Bristlenose pleco | 5 in | 30 gal |
| Betta | 3 in | 4 gal |
Water ranges: Aqueon’s cover the whole group in its care guide (e.g. “most livebearers”), LiveAquaria’s (LA) the one listing. Aqueon says white clouds share the danios’ needs, so its danio figures are shown.
| Species | Temp. °F (Aqueon / LA) | pH (Aqueon / LA) |
|---|---|---|
| Guppy | 74-78 / 64-82 | 7.0-8.4 / 5.5-8.0 |
| Platy | 74-78 / 64-77 | 7.0-8.4 / 7.0-8.2 |
| Zebra danio | 70-78 / 64-75 | 7.0-7.8 / 6.5-7.5 |
| White cloud | 70-78 (danio guide) / 65-77 (Co-Op) | 7.0-7.8 (danio guide) / 6.5-8.5 (Co-Op) |
| Neon tetra | 75-80 / 68-78 | 6.8-7.8 / 5.5-7.0 |
| Harlequin rasbora | 75-80 / 72-77 | 6.8-7.8 / 6.0-6.5 |
| Cherry barb | 75-80 / 74-79 | 6.8-7.8 / 6.0-7.0 |
| Panda cory | 74-80 / 72-79 | 7.0-8.0 / 5.8-7.0 |
| Bristlenose pleco | 74-80 / 72-79 | 7.0-8.0 / 6.5-7.4 |
| Betta | 76-85 / 75-86 | 6.8-7.5 / 6.0-8.0 |
The Species, One by One
Guppy (Poecilia reticulata) and Platy (Xiphophorus maculatus)
- Who recommends them: Aqueon’s livebearer guide says livebearers “make great beginner fish because they tend to be peaceful, colorful and hardy.” LiveAquaria calls the platy “an easy-care fish perfect for beginning aquarists” and lists both as “Care Level: Easy”. Aquarium Co-Op disagrees in part: it says many beginners choose “popular fish like fancy guppies and neon tetras that can sometimes come with unexpected health issues”.
- Tank: Aqueon says guppies, platies and common mollies “will all do well in tanks under 10 gallons”; LiveAquaria lists a 10-gallon minimum for both. Sources differ.
- Group and temperament: Aqueon advises at least 3, “preferably 1 male and 2-3 females”, because “Males can be quite aggressive when it comes to breeding.” It adds: “if you have male and female livebearers, you will eventually have fry – plan accordingly!” LiveAquaria lists both as “Temperament: Peaceful”.
- Diet and water: Aqueon says livebearers “need both vegetable matter and meat-based foods” and are “native to hard, alkaline water, but farm raised fish sold today will thrive in a wide range of water conditions.”
Zebra Danio (Danio rerio)
- Who recommends it: Aqueon’s first-60-days guide lists “Zebra, Leopard & Pearl Danios” among its suggested starter fish, and its danio guide calls danios “excellent fish for beginners and newly set up aquariums.”
- Tank: LiveAquaria lists 3 in and 10 gallons, while Aqueon says most danio species grow to less than 2 in; sources differ.
- Group and temperament: Aqueon: “Danios are best kept in schools of at least 6 or more.” They are “active, to the point of being boisterous, but rarely cause injury to other fish.”
- Diet: Aqueon: “Most danios are omnivorous”.
White Cloud Mountain Minnow (Tanichthys albonubes)
- Who recommends it: Aqueon’s starter list names “White Cloud Minnows”. Aquarium Co-Op calls it “one of our favorite beginner fish”.
- Tank and group: Co-Op describes “This 1.5-inch (4 cm) minnow” and advises “a group of at least six” in “a 10-gallon tank or larger.”
- Water: Co-Op 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’s heater advice differs; see the item on a room colder than your fish’s range, below.
- Temperament and diet: Asked whether white clouds are aggressive, Co-Op answers “Not usually”; it says they “are happy to eat almost any fish food that is small enough to fit in their mouths.”
Neon Tetra (Paracheirodon innesi)
- Who recommends it: Aqueon’s tetra guide says “Popular beginner tetras include red eye, black skirt, serpae and bloodfins”, and that “neons, black neons, glowlights and lemon tetras can be good choices as well.” LiveAquaria lists “Care Level: Easy”.
- Tank: Aqueon says “Most tetras can be kept in aquariums of 10 to 20 gallons”; LiveAquaria lists 10 gallons. For 5- to 10-gallon tanks, Aqueon advises to “avoid the more torpedo shaped tetras like neons and cardinals”. 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.” Sources differ on the pleco’s tank size; see the bristlenose entry.
- Group and temperament: Aqueon says tetras “do best in schools of 6 or more”. LiveAquaria calls the neon “Extremely peaceful”.
- Diet: omnivore, per LiveAquaria.
Harlequin Rasbora (Rasbora heteromorpha)
- Who recommends it: Aqueon’s starter list names “Harlequin Rasboras”. Its rasbora guide says harlequins and similar species “typically do not get larger than 2 inches” and are “good beginner fish for 10-gallon aquariums or larger.”
- Group: Aqueon: “groups of 7 or more”. LiveAquaria: “schools of 8-10 individuals”.
- Water: Aqueon’s range is for commercially raised fish; it says “Wild-caught fish prefer a pH of 5.0 to 7.0”. Aqueon’s 6.8-7.8 and LiveAquaria’s 6.0-6.5 do not overlap.
- Temperament and diet: Aqueon says “Rasboras are peaceful” and that most are “micro-predators”; it says they “will thrive on” flakes, granules and shrimp pellets. LiveAquaria lists “Diet: Omnivore”.
Cherry Barb (Puntius titteya)
- Who recommends it: Aqueon’s starter list names “Cherry Barbs”, and its barb guide lists cherry barbs among the peaceful species “that make great community tank inhabitants.”
- Tank: Aqueon: “Small species like cherry and gold barbs can be kept in 10 to 20 gallon aquariums.” LiveAquaria lists a 20-gallon minimum, and its description says “They prefer a well-planted tank of at least 30 gallons”. Sources differ.
- Group and temperament: Aqueon: barbs “do best in schools of at least 6 to 10 fish”. LiveAquaria calls the cherry barb “a very timid fish that should be housed with fish of the same temperament.”
- Diet: LiveAquaria: “a variety of foods including vegetables as well as meaty foods.”
Panda Cory (Corydoras panda)
- Who recommends it: Aqueon’s starter list names “Corydoras Catfish”, and its tank-size guide calls the panda cory and the salt and pepper cory (Corydoras paleatus) “good choices” for 5- to 10-gallon tanks.
- Caution: Aqueon’s Corydoras guide says: “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.” It also says some species “have a mild toxin in their spines”, so “Care should be taken when handling them”.
- Tank: sources differ. The same Corydoras guide says “A 30-gallon aquarium is best for most species”, with pygmy species kept in smaller tanks; LiveAquaria lists 30 gallons for the panda.
- Group: Aqueon’s care guide says “groups of 5 or more”; LiveAquaria says “six or more”.
- Diet: Aqueon: “it is important to feed them directly and not just depend on them getting leftovers from feeding other fish.”
Bristlenose Pleco (Ancistrus sp.)
- Who recommends it: Aqueon’s beginner-fish guide names it as the pleco to choose in 20- to 50-gallon tanks: “A much better choice is the Bristlenose pleco (Ancistrus sp.) which maintains a small size”. LiveAquaria lists its albino gold bushy nose listing as “Care Level: Easy”.
- Tank: sources differ. LiveAquaria gives “A recommended minimum tank of 30 gallons” for that listing (5 in). Aqueon’s 5- to 10-gallon section allows “a bristlenose pleco” with a neon school; its main bristlenose line is in its 20- to 50-gallon section.
- Diet: Aqueon: “it should be fed specifically and not just dependent on algae and scraps”, with sinking wafers or “sliced cucumber”, which “must be attached or weighted down”. Our tropical fish food roundup covers flakes, granules and pellets.
- Temperament: LiveAquaria: “Bushy Nose Plecos make good additions to any community aquarium.” Aqueon says plecos “tend to be secretive”, so give them caves or other hiding places.
Betta (Betta splendens)
- Who recommends it: Aqueon’s starter list names “Bettas”; LiveAquaria calls the betta “a favorite of both beginning and advanced hobbyists”.
- Tank and tankmates: LiveAquaria says it “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.” It advises: “Avoid putting them with male gouramis, fin-nippers such as tiger barbs or active fish like giant danios.”
- More: see our betta fish food roundup and our guide to reducing filter current for bettas. LiveAquaria lists “Diet: Carnivore”.
Before You Buy: The Must-Haves
A cycling plan
API, a test-kit maker, names two ways to cycle a new tank. It 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”, and its guide then focuses on the fish-in cycle. In that fish-in guide, API first adds its own conditioner and bacteria starter (API Stress Coat and API Quick Start); then “it is recommended to add small amounts of fish at a time”, and cycling is complete “when the readings show 0ppm Ammonia, 0ppm Nitrite and 5ppm-20ppm Nitrate”. Aqueon says cycling “begins after you add the first fish”. Our guide to cycling a fish tank gives the steps for both ways.
A test kit for ammonia, nitrite, nitrate and pH
API says its Freshwater Master Test Kit “measures pH, high range pH, ammonia, nitrite, and nitrate”. Its ammonia test strip page says “In new aquariums, ammonia should be tested every other day until the ammonia level measures 0 parts per million (ppm) or mg/L.” Its nitrite kit page says “Water should be tested for nitrite every other day when your aquarium or pond is first set up, and once a week after the biological filter has been established (in about 4-6 weeks)”, while its fish-in cycling guide says “Testing should occur every 3-4 days.” Aqueon, an aquarium maker, says “The only safe ammonia level is zero” and “The only safe nitrite level is zero”; for nitrate, toxicity “varies depending on species, age and overall health, but levels above 50 ppm are undesirable in freshwater aquaria.” For a reading above zero, see how to lower ammonia or how to lower nitrites.
Room for the adult fish and its group
Aqueon: “Don’t overstock your aquarium. Fish that are crowded may fight, and overstocking can lead to water quality problems.”
A secure lid
Most of Aqueon’s guides here repeat it, e.g. “Keep a secure lid on the aquarium to prevent fish from jumping out if they feel scared or threatened.” Aqueon’s betta guide says “bettas are jumpers”.
A water conditioner for tap water
Aqueon: “Always treat tap water with a water conditioner to neutralize chlorine and ammonia before adding it to the aquarium.” The three conditioners below are compared in our water conditioner roundup, which describes API Tap Water Conditioner as “a plain, low-cost dechlorinator for water changes” and Seachem Prime as for keepers “on chloraminated tap water, or cycling a new tank”.
| # | Preview | Product | Price | Link |
|---|---|---|---|---|
| 1 |  | Aqueon Fish Tank Water Conditioner Bottle, 16 Oz | Water…Everyday ammonia detox | $11.49 Prime | Check on Amazon |
| 2 |  | API TAP WATER CONDITIONER Aquarium Water Conditioner…Budget dechlorinator | Check on Amazon | |
| 3 |  | Seachem Prime -500 ml/ 17 fl. oz. | Chemical Remover and…Concentrated ammonia binder | $16.62 Prime | Check on Amazon |
Nice to Have
- Sand or fine gravel for Corydoras. Aqueon: “Substrate should be sand or fine gravel with rounded edges.” Our aquarium sand roundup covers grain size.
- A quarantine tank. Our guide to quarantining new fish covers the tank, the gear and the timing.
What Changes the List
- A 5- to 10-gallon tank. Aqueon says fish for these tanks should be small, generally ½ in to 2 in at most: “The bigger they are, the fewer you want to keep”, and that “these size tanks do not lend themselves to schools of fish.” It advises: “It is best to avoid the swordtails and the sailfin mollies if your aquarium is under 10 gallons”. Most LiveAquaria listings above start at 10 gallons; the betta’s starts at 4.
- A brand-new tank. Aqueon advises letting the aquarium “settle” for “at least 48 hours before buying your first fish”. It says “Once ammonia and nitrite levels return to zero your aquarium has completed its first cycle. You may now introduce additional fish.” Its danio guide calls danios suited to “newly set up aquariums”, while its Corydoras guide says corys “should never be added to new aquariums”.
- A room colder than your fish’s range. Aqueon’s heater advice is conditional; for livebearers: “If the aquarium is kept in a room below 74° F, use an Aqueon Aquarium Heater to maintain the correct temperature.” Its danio guide, which covers white clouds, sets it at 70°. Aquarium Co-Op says white clouds “can readily live in a fish tank with no heater”. Sources differ, so check your room temperature against each range. Our aquarium heater roundup sorts heaters by tank size.
- Your tap water. Compare its pH with each range in the table; for the harlequin rasbora the two sources’ ranges do not overlap. Aqueon says most tetras and barbs sold today are raised commercially “in water that often has a higher pH and alkalinity than their native environments”.
- The fish you already have. Aqueon’s barb guide warns: “Some barbs communicate by nipping at each other, so avoid mixing these fish with timid, slow moving or long-finned fish such as neon tetras, angelfish, guppies or bettas.”
Commonly Sold Fish Where Sources Give Large Tank Sizes
| Fish | What it needs | Source |
|---|---|---|
| Common pleco | Over 12 in; at least 75 gal (LiveAquaria’s albino listing: 22 in, 120 gal) | Aqueon, LiveAquaria |
| Tinfoil barb | 125 gal or larger as an adult | Aqueon |
| Giant danio | Larger aquariums only | Aqueon |
| Swordtail, sailfin molly | Not under 10 gal | Aqueon |
| Black molly (one listing) | 5 in max; 30 gal minimum; care level moderate | LiveAquaria |
Sources differ on mollies: Aqueon’s livebearer guide, which covers mollies, calls livebearers “great beginner fish” and its tank-size guide places common mollies in tanks under 10 gallons, while LiveAquaria’s black molly listing starts at 30.
Ready to buy?
Our water conditioner roundup compares conditioners for tap water, and our freshwater test kit roundup compares kits for ammonia, nitrite and nitrate.
Frequently Asked Questions
Q. How many fish can I add at once?
Aqueon advises: “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.”
Q. Which beginner fish can live together?
Aqueon lists “tetras, rasboras, danios, peaceful barbs and rainbowfish” as good tankmates for livebearers. Its barb guide warns against mixing nipping barbs with “timid, slow moving or long-finned fish such as neon tetras, angelfish, guppies or bettas.”
Q. Are goldfish good beginner fish?
Aqueon’s suggested starter list does not name goldfish, and its goldfish guide says “Goldfish should never be kept in bowls, small aquariums or any unfiltered container!” and that 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.” See why goldfish die in an aquarium.
Q. How often should I change the water?
Aqueon’s first-60-days guide says “There are different philosophies on how much and how often to change water, but 10% to 25% every 1 to 2 weeks is a good rule of thumb. Small frequent water changes are best.”
Q. What should I do if a new fish looks sick?
Test the water for ammonia and nitrite first, since Aqueon says the only safe level of each is zero, and contact an aquatic veterinarian. This site gives no disease treatment or medication advice.
Sources (29)
- Aqueon (maker), Best Beginner Fish by Tank Size
- Aqueon (maker), Starting A New Aquarium: The First 60 Days
- Aqueon (maker), Livebearer Care Guide
- Aqueon (maker), Danios Care Guide
- Aqueon (maker), Tetras Care Guide
- Aqueon (maker), Rasboras Care Guide
- Aqueon (maker), Barbs Care Guide
- Aqueon (maker), Corydoras Catfish Care Guide
- Aqueon (maker), Plecostomus Care Guide
- Aqueon (maker), Betta Care Guide
- Aqueon (maker), Goldfish Care Guide
- Aqueon (maker), Freshwater Aquarium Water Quality
- Aqueon (maker), Aquarium Do’s and Don’ts
- API (test-kit maker), Freshwater Master Test Kit
- API (test-kit maker), Ammonia Test Strips
- API (test-kit maker), Nitrite Test Kit
- API (test-kit maker), How to Cycle a New Tank?
- Aquarium Co-Op (retailer), Care Guide for White Cloud Mountain Minnows
- LiveAquaria (retailer), Assorted Guppy Group, Male
- LiveAquaria (retailer), Assorted Platy
- LiveAquaria (retailer), Zebra Danio
- LiveAquaria (retailer), Neon Tetra
- LiveAquaria (retailer), Harlequin Rasbora
- LiveAquaria (retailer), Cherry Barb
- LiveAquaria (retailer), Panda Cory Cat
- LiveAquaria (retailer), Bushy Nose Plecostomus, Albino Gold
- LiveAquaria (retailer), Veiltail Betta, Male
- LiveAquaria (retailer), Black Molly
- LiveAquaria (retailer), Albino Glass Cleaner Plecostomus
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