Aquariumtetra · freshwater
Penguin Tetra: adult size, tank size & tankmates
The Penguin Tetra (Thayeria boehlkei) grows to about 1.7 in (3.6 cm SL). It needs a tank at least 24 inches long and about 18 gallons. Keep at least 6 together, at 72–82°F.
How big it really gets
Drawn to scale against common tank lengths. Green bars meet the minimum tank length from our sources.
Will it fit your tank?
Quick facts
- Adult size
- 1.7 in (3.6 cm SL)
- Minimum tank
- 24 inches long and about 18 gallons
- Temperature
- 72–82°F
- pH
- 5.5–8
- Hardness
- 0–20 dGH
- Group size
- 6+
- With other fish
- peaceful
- With its own kind
- peaceful
- Swims
- middle of the tank
- Diet
- omnivore
- Care level
- beginner
- Lifespan
- not stated in sources
Watch for: nips fins · may eat baby shrimp
Penguin Tetra tankmates
Checked with the same rules as our tank builder: temperature overlap, pH and hardness, predation and mouth size, fin-nipping and temperament. Tank size is left out here; check it in the builder.
Good tankmates
- Neon TetraAdult ~1.4 in · 70–77°F
- Cardinal TetraAdult ~1.7 in · 73–84°F
- Harlequin RasboraAdult ~2.1 in · 70–82°F
- Ember TetraAdult ~0.9 in · 68–82°F
- Chili RasboraAdult ~0.9 in · 68–82°F
- Celestial Pearl DanioAdult ~1 in · 68–79°F
- Cherry BarbAdult ~2.4 in · 68–81°F
- Rummy-nose TetraAdult ~2.4 in · 73–79°F
- Black Neon TetraAdult ~1.7 in · 73–82°F
- Glowlight TetraAdult ~1.9 in · 75–82°F
Use caution
- GuppyPenguin Tetra nips fins, and Guppy has long fins.
- Honey GouramiPenguin Tetra nips fins, and Honey Gourami has long fins.
- Dwarf GouramiNeeds carePenguin Tetra nips fins, and Dwarf Gourami has long fins.
- Pearl GouramiPenguin Tetra nips fins, and Pearl Gourami has long fins.
- German Blue RamNeeds carePenguin Tetra and German Blue Ram only share 81–82°F. That's a tight window.
- AngelfishNeeds carePenguin Tetra nips fins, and Angelfish has long fins.
- Cherry ShrimpPenguin Tetra may eat baby Cherry Shrimp. Adults are usually safe, but expect fewer shrimplets.
- Amano ShrimpPenguin Tetra may eat baby Amano Shrimp. Adults are usually safe, but expect fewer shrimplets.
Avoid
- BettaNeeds carePenguin Tetra nips fins, and Betta has long fins.
- Chinese Algae EaterOutgrows tanksChinese Algae Eater grows 8× longer than Penguin Tetra and may treat it as food.
- Common / Comet GoldfishOutgrows tanksCommon / Comet Goldfish eats small fish, and Penguin Tetra only grows to about 1.7 in.
- Convict CichlidNeeds careConvict Cichlid is aggressive toward tankmates. Penguin Tetra is peaceful.
- Electric Blue AcaraNeeds careElectric Blue Acara eats small fish, and Penguin Tetra only grows to about 1.7 in.
- Fancy GoldfishOutgrows tanksPenguin Tetra (72–82°F) and Fancy Goldfish (50–70°F) need different temperatures.
- Iridescent SharkOutgrows tanksIridescent Shark eats small fish, and Penguin Tetra only grows to about 1.7 in.
- OscarOutgrows tanksOscar eats small fish, and Penguin Tetra only grows to about 1.7 in.
All 105 species we checked against the Penguin Tetra
| Species | Verdict | Why |
|---|---|---|
| African Dwarf Frog | Compatible | No conflicts found |
| Assassin Snail | Compatible | No conflicts found |
| Bala Shark | Compatible | No conflicts found |
| Black Neon Tetra | Compatible | No conflicts found |
| Bleeding Heart Tetra | Compatible | No conflicts found |
| Bolivian Ram | Compatible | No conflicts found |
| Bristlenose Pleco | Compatible | No conflicts found |
| Bronze Cory | Compatible | No conflicts found |
| Bumblebee Goby | Compatible | No conflicts found |
| Cardinal Tetra | Compatible | No conflicts found |
| Celestial Pearl Danio | Compatible | No conflicts found |
| Cherry Barb | Compatible | No conflicts found |
| Chili Rasbora | Compatible | No conflicts found |
| Clown Killifish | Compatible | No conflicts found |
| Clown Loach | Compatible | No conflicts found |
| Clown Pleco | Compatible | No conflicts found |
| Cockatoo Dwarf Cichlid | Compatible | No conflicts found |
| Common Pleco | Compatible | No conflicts found |
| Denison Barb | Compatible | No conflicts found |
| Diamond Tetra | Compatible | No conflicts found |
| Discus | Compatible | No conflicts found |
| Dwarf Neon Rainbowfish | Compatible | No conflicts found |
| Ember Tetra | Compatible | No conflicts found |
| Endler's Livebearer | Compatible | No conflicts found |
| Forktail Blue-eye | Compatible | No conflicts found |
| Giant Danio | Compatible | No conflicts found |
| Glass Catfish | Compatible | No conflicts found |
| Glowlight Tetra | Compatible | No conflicts found |
| Gold Barb | Compatible | No conflicts found |
| Harlequin Rasbora | Compatible | No conflicts found |
| Head-and-tail-light Tetra | Compatible | No conflicts found |
| Hillstream Loach | Compatible | No conflicts found |
| Japanese Trapdoor Snail | Compatible | No conflicts found |
| Julii Cory | Compatible | No conflicts found |
| Kribensis | Compatible | No conflicts found |
| Kuhli Loach | Compatible | No conflicts found |
| Lambchop Rasbora | Compatible | No conflicts found |
| Lemon Tetra | Compatible | No conflicts found |
| Malaysian Trumpet Snail | Compatible | No conflicts found |
| Marbled Hatchetfish | Compatible | No conflicts found |
| Molly | Compatible | No conflicts found |
| Neon Tetra | Compatible | No conflicts found |
| Nerite Snail | Compatible | No conflicts found |
| Odessa Barb | Compatible | No conflicts found |
| Otocinclus | Compatible | No conflicts found |
| Panda Cory | Compatible | No conflicts found |
| Pea Puffer | Compatible | No conflicts found |
| Pearl Danio | Compatible | No conflicts found |
| Peppered Cory | Compatible | No conflicts found |
| Platy | Compatible | No conflicts found |
| Pristella Tetra | Compatible | No conflicts found |
| Pygmy Cory | Compatible | No conflicts found |
| Ramshorn Snail | Compatible | No conflicts found |
| Rosy Barb | Compatible | No conflicts found |
| Rummy-nose Tetra | Compatible | No conflicts found |
| Scissortail Rasbora | Compatible | No conflicts found |
| Serpae Tetra | Compatible | No conflicts found |
| Siamese Algae Eater | Compatible | No conflicts found |
| Silver Hatchetfish | Compatible | No conflicts found |
| Silver Tip Tetra | Compatible | No conflicts found |
| Sparkling Gourami | Compatible | No conflicts found |
| Sterbai Cory | Compatible | No conflicts found |
| Swordtail | Compatible | No conflicts found |
| Upside-down Catfish | Compatible | No conflicts found |
| Variatus Platy | Compatible | No conflicts found |
| Weather Loach | Compatible | No conflicts found |
| Zebra Danio | Compatible | No conflicts found |
| Amano Shrimp | Caution | Penguin Tetra may eat baby Amano Shrimp. Adults are usually safe, but expect fewer shrimplets. |
| Angelfish | Caution | Penguin Tetra nips fins, and Angelfish has long fins.; Angelfish can bully smaller, peaceful Penguin Tetra. |
| Bamboo Shrimp | Caution | Penguin Tetra may eat baby Bamboo Shrimp. Adults are usually safe, but expect fewer shrimplets. |
| Black Skirt Tetra | Caution | Black Skirt Tetra can bully smaller, peaceful Penguin Tetra. |
| Blood Parrot Cichlid | Caution | Blood Parrot Cichlid can bully smaller, peaceful Penguin Tetra. |
| Boesemani Rainbowfish | Caution | Penguin Tetra and Boesemani Rainbowfish only share 81–82°F. That's a tight window. |
| Buenos Aires Tetra | Caution | Buenos Aires Tetra can bully smaller, peaceful Penguin Tetra. |
| Cherry Shrimp | Caution | Penguin Tetra may eat baby Cherry Shrimp. Adults are usually safe, but expect fewer shrimplets. |
| Congo Tetra | Caution | Penguin Tetra nips fins, and Congo Tetra has long fins. |
| Crystal Red Shrimp | Caution | Penguin Tetra may eat baby Crystal Red Shrimp. Adults are usually safe, but expect fewer shrimplets. |
| Dwarf Gourami | Caution | Penguin Tetra nips fins, and Dwarf Gourami has long fins.; Dwarf Gourami can bully smaller, peaceful Penguin Tetra. |
| Electric Yellow Lab | Caution | Electric Yellow Lab can bully smaller, peaceful Penguin Tetra. |
| Firemouth Cichlid | Caution | Firemouth Cichlid can bully smaller, peaceful Penguin Tetra. |
| German Blue Ram | Caution | Penguin Tetra and German Blue Ram only share 81–82°F. That's a tight window. |
| Ghost Shrimp | Caution | Penguin Tetra may eat baby Ghost Shrimp. Adults are usually safe, but expect fewer shrimplets. |
| Guppy | Caution | Penguin Tetra nips fins, and Guppy has long fins. |
| Honey Gourami | Caution | Penguin Tetra nips fins, and Honey Gourami has long fins. |
| Kissing Gourami | Caution | Kissing Gourami grows 7× longer than Penguin Tetra and may treat it as food.; Kissing Gourami can bully smaller, peaceful Penguin Tetra. |
| Moonlight Gourami | Caution | Penguin Tetra nips fins, and Moonlight Gourami has long fins. |
| Mystery Snail | Caution | Penguin Tetra (pH 5.5–8) and Mystery Snail (pH unknown) prefer different pH.; Penguin Tetra (0–20 dGH) and Mystery Snail (unknown dGH) prefer different water hardness. |
| Paradise Fish | Caution | Penguin Tetra and Paradise Fish only share 72–72°F. That's a tight window.; Paradise Fish can bully smaller, peaceful Penguin Tetra. |
| Pearl Gourami | Caution | Penguin Tetra nips fins, and Pearl Gourami has long fins. |
| Rainbow Shark | Caution | Rainbow Shark grows 4× longer than Penguin Tetra and may treat it as food.; Rainbow Shark can bully smaller, peaceful Penguin Tetra. |
| Red-Tail Shark | Caution | Red-Tail Shark can bully smaller, peaceful Penguin Tetra. |
| Three-spot Gourami | Caution | Three-spot Gourami grows 4× longer than Penguin Tetra and may treat it as food.; Three-spot Gourami can bully smaller, peaceful Penguin Tetra. |
| Tiger Barb | Caution | Tiger Barb can bully smaller, peaceful Penguin Tetra. |
| White Cloud Mountain Minnow | Caution | Penguin Tetra and White Cloud Mountain Minnow only share 72–72°F. That's a tight window. |
| Yoyo Loach | Caution | Yoyo Loach grows 4× longer than Penguin Tetra and may treat it as food.; Yoyo Loach can bully smaller, peaceful Penguin Tetra. |
| Betta | Avoid | Penguin Tetra nips fins, and Betta has long fins.; Betta can bully smaller, peaceful Penguin Tetra. |
| Chinese Algae Eater | Avoid | Chinese Algae Eater grows 8× longer than Penguin Tetra and may treat it as food.; Chinese Algae Eater is aggressive toward tankmates. Penguin Tetra is peaceful. |
| Common / Comet Goldfish | Avoid | Common / Comet Goldfish eats small fish, and Penguin Tetra only grows to about 1.7 in. |
| Convict Cichlid | Avoid | Convict Cichlid is aggressive toward tankmates. Penguin Tetra is peaceful. |
| Electric Blue Acara | Avoid | Electric Blue Acara eats small fish, and Penguin Tetra only grows to about 1.7 in. |
| Fancy Goldfish | Avoid | Penguin Tetra (72–82°F) and Fancy Goldfish (50–70°F) need different temperatures.; Penguin Tetra nips fins, and Fancy Goldfish has long fins. |
| Iridescent Shark | Avoid | Iridescent Shark eats small fish, and Penguin Tetra only grows to about 1.7 in. |
| Oscar | Avoid | Oscar eats small fish, and Penguin Tetra only grows to about 1.7 in. |
| Pictus Catfish | Avoid | Pictus Catfish eats small fish, and Penguin Tetra only grows to about 1.7 in. |
| Tinfoil Barb | Avoid | Tinfoil Barb eats small fish, and Penguin Tetra only grows to about 1.7 in. |
Care notes
Needs: Keep in numbers to prevent fin nipping; does not compete well with boisterous or much larger tankmates.
Group: SF: at least 6, preferably 10+; nipping appears when kept in too-small numbers.
Temperament: peaceful toward other fish, peaceful toward its own kind. Lives in the middle of the tank.
Common questions
How big does a Penguin Tetra get?
About 1.7 inches (3.6 cm SL) as an adult, according to seriouslyfish.com.
What size tank does a Penguin Tetra need?
At least 24 inches long and about 18 gallons. The smallest standard tank that meets that is a 20 gallon long.
How many Penguin Tetras should be kept together?
At least 6. SF: at least 6, preferably 10+; nipping appears when kept in too-small numbers.
What fish can live with a Penguin Tetra?
Species that passed every check include Neon Tetra, Cardinal Tetra, Harlequin Rasbora, Ember Tetra, Chili Rasbora, Celestial Pearl Danio.
Gear for a Penguin Tetra setup
TankSmallest standard tank that meets its minimum: 20 gallon long (30 in long).Find on Amazon →HeaterAbout 100 W for 20 gallons, holding 72–82°F.Find on Amazon →FoodA quality flake or micro-pellet as a staple.Find on Amazon →Test kitCheck ammonia, nitrite and pH. Cycle the tank before adding fish.Find on Amazon →
As an Amazon Associate, AquariumSetup earns from qualifying purchases. Links open Amazon search results so you can compare current options.
Related guides
Sources
Values come from these pages, in our own words. Status: researched from source pages. Last reviewed 2026-10-12.
- seriouslyfish.com /species/thayeria-boehlkei/
- fishbase.se /summary/Thayeria-boehlkei.html