Aquariumlivebearer · freshwater
Swordtail: adult size, tank size & tankmates
The Swordtail (Xiphophorus hellerii) grows to about 6.6 in (14 cm SL). It needs a tank at least 47 inches long and about 29 gallons. Keep at least 6 together, at 61–82°F.
How big it really gets
Drawn to scale against common tank lengths. Green bars meet the minimum tank length from our sources.
Needs special care. Sold as a small community livebearer but needs a 120 cm (about 4 ft) tank; routinely put in 10-20 gallon tanks.
Will it fit your tank?
Quick facts
- Adult size
- 6.6 in (14 cm SL)
- Minimum tank
- 47 inches long and about 29 gallons
- Temperature
- 61–82°F
- pH
- 7–8
- Hardness
- 10–25 dGH
- Group size
- 6+
- With other fish
- peaceful
- With its own kind
- semi-aggressive
- Swims
- middle of the tank
- Diet
- omnivore
- Care level
- intermediate
- Lifespan
- not stated in sources
Watch for: eats shrimp · jumps, so keep a lid
Swordtail 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
- German Blue RamNeeds careSwordtail and German Blue Ram only share 81–82°F. That's a tight window.
- Pygmy CorySwordtail (10–25 dGH) and Pygmy Cory (0–8 dGH) prefer different water hardness.
- Kuhli LoachSwordtail (10–25 dGH) and Kuhli Loach (0–8 dGH) prefer different water hardness.
- Mystery SnailSwordtail (pH 7–8) and Mystery Snail (pH unknown) prefer different pH.
- Boesemani RainbowfishSwordtail and Boesemani Rainbowfish only share 81–82°F. That's a tight window.
- Clown KillifishSwordtail (10–25 dGH) and Clown Killifish (1–8 dGH) prefer different water hardness.
- Cockatoo Dwarf CichlidSwordtail (pH 7–8) and Cockatoo Dwarf Cichlid (pH 5–6) prefer different pH.
- DiscusNeeds careSwordtail (10–25 dGH) and Discus (0–5 dGH) prefer different water hardness.
Avoid
- Cherry ShrimpSwordtail will eat Cherry Shrimp.
- Amano ShrimpSwordtail will eat Amano Shrimp.
- Bamboo ShrimpSwordtail will eat Bamboo Shrimp.
- Chinese Algae EaterOutgrows tanksChinese Algae Eater is aggressive toward tankmates. Swordtail is peaceful.
- Convict CichlidNeeds careConvict Cichlid is aggressive toward tankmates. Swordtail is peaceful.
- Crystal Red ShrimpSwordtail will eat Crystal Red Shrimp.
- Ghost ShrimpSwordtail will eat Ghost Shrimp.
All 105 species we checked against the Swordtail
| Species | Verdict | Why |
|---|---|---|
| African Dwarf Frog | Compatible | No conflicts found |
| Angelfish | Compatible | No conflicts found |
| Assassin Snail | Compatible | No conflicts found |
| Bala Shark | Compatible | No conflicts found |
| Betta | Compatible | No conflicts found |
| Black Neon Tetra | Compatible | No conflicts found |
| Black Skirt Tetra | Compatible | No conflicts found |
| Bleeding Heart Tetra | Compatible | No conflicts found |
| Blood Parrot Cichlid | Compatible | No conflicts found |
| Bolivian Ram | Compatible | No conflicts found |
| Bristlenose Pleco | Compatible | No conflicts found |
| Bronze Cory | Compatible | No conflicts found |
| Buenos Aires Tetra | 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 Loach | Compatible | No conflicts found |
| Clown Pleco | Compatible | No conflicts found |
| Common / Comet Goldfish | Compatible | No conflicts found |
| Common Pleco | Compatible | No conflicts found |
| Congo Tetra | Compatible | No conflicts found |
| Denison Barb | Compatible | No conflicts found |
| Diamond Tetra | Compatible | No conflicts found |
| Dwarf Gourami | Compatible | No conflicts found |
| Dwarf Neon Rainbowfish | Compatible | No conflicts found |
| Electric Blue Acara | Compatible | No conflicts found |
| Electric Yellow Lab | Compatible | No conflicts found |
| Ember Tetra | Compatible | No conflicts found |
| Endler's Livebearer | Compatible | No conflicts found |
| Fancy Goldfish | Compatible | No conflicts found |
| Firemouth Cichlid | 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 |
| Guppy | 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 |
| Honey Gourami | Compatible | No conflicts found |
| Iridescent Shark | Compatible | No conflicts found |
| Japanese Trapdoor Snail | Compatible | No conflicts found |
| Julii Cory | Compatible | No conflicts found |
| Kribensis | 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 |
| Moonlight Gourami | 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 |
| Paradise Fish | Compatible | No conflicts found |
| Pea Puffer | Compatible | No conflicts found |
| Pearl Danio | Compatible | No conflicts found |
| Pearl Gourami | Compatible | No conflicts found |
| Penguin Tetra | Compatible | No conflicts found |
| Peppered Cory | Compatible | No conflicts found |
| Platy | Compatible | No conflicts found |
| Pristella Tetra | Compatible | No conflicts found |
| Rainbow Shark | Compatible | No conflicts found |
| Ramshorn Snail | Compatible | No conflicts found |
| Red-Tail Shark | 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 |
| Three-spot Gourami | Compatible | No conflicts found |
| Tiger Barb | Compatible | No conflicts found |
| Tinfoil Barb | Compatible | No conflicts found |
| Upside-down Catfish | Compatible | No conflicts found |
| Variatus Platy | Compatible | No conflicts found |
| Weather Loach | Compatible | No conflicts found |
| White Cloud Mountain Minnow | Compatible | No conflicts found |
| Yoyo Loach | Compatible | No conflicts found |
| Zebra Danio | Compatible | No conflicts found |
| Boesemani Rainbowfish | Caution | Swordtail and Boesemani Rainbowfish only share 81–82°F. That's a tight window. |
| Clown Killifish | Caution | Swordtail (10–25 dGH) and Clown Killifish (1–8 dGH) prefer different water hardness. |
| Cockatoo Dwarf Cichlid | Caution | Swordtail (pH 7–8) and Cockatoo Dwarf Cichlid (pH 5–6) prefer different pH. |
| Discus | Caution | Swordtail (10–25 dGH) and Discus (0–5 dGH) prefer different water hardness. |
| German Blue Ram | Caution | Swordtail and German Blue Ram only share 81–82°F. That's a tight window. |
| Kissing Gourami | Caution | Kissing Gourami can bully smaller, peaceful Swordtail. |
| Kuhli Loach | Caution | Swordtail (10–25 dGH) and Kuhli Loach (0–8 dGH) prefer different water hardness. |
| Mystery Snail | Caution | Swordtail (pH 7–8) and Mystery Snail (pH unknown) prefer different pH.; Swordtail (10–25 dGH) and Mystery Snail (unknown dGH) prefer different water hardness. |
| Oscar | Caution | Oscar can bully smaller, peaceful Swordtail. |
| Pictus Catfish | Caution | Swordtail (pH 7–8) and Pictus Catfish (pH 5.8–6.8) prefer different pH. |
| Pygmy Cory | Caution | Swordtail (10–25 dGH) and Pygmy Cory (0–8 dGH) prefer different water hardness. |
| Amano Shrimp | Avoid | Swordtail will eat Amano Shrimp. |
| Bamboo Shrimp | Avoid | Swordtail will eat Bamboo Shrimp. |
| Cherry Shrimp | Avoid | Swordtail will eat Cherry Shrimp. |
| Chinese Algae Eater | Avoid | Chinese Algae Eater is aggressive toward tankmates. Swordtail is peaceful. |
| Convict Cichlid | Avoid | Convict Cichlid is aggressive toward tankmates. Swordtail is peaceful. |
| Crystal Red Shrimp | Avoid | Swordtail will eat Crystal Red Shrimp.; Swordtail (10–25 dGH) and Crystal Red Shrimp (4–6 dGH) prefer different water hardness. |
| Ghost Shrimp | Avoid | Swordtail will eat Ghost Shrimp. |
Care notes
Needs: Large, long tank (SF minimum 120 cm footprint) with a steady pH in hard, alkaline water; secure lid; limit males to reduce fighting.
Group: SF: needs to be in a group (number not stated; 6 editorial). Males form dominance hierarchies and are aggressive to each other in confined tanks (SF, FishBase); keep females in the majority.
Temperament: peaceful toward other fish, semi-aggressive toward its own kind. Lives in the middle of the tank.
Common questions
How big does a Swordtail get?
About 6.6 inches (14 cm SL) as an adult, according to seriouslyfish.com.
What size tank does a Swordtail need?
At least 47 inches long and about 29 gallons. The smallest standard tank that meets that is a 55 gallon.
How many Swordtails should be kept together?
At least 6. SF: needs to be in a group (number not stated; 6 editorial). Males form dominance hierarchies and are aggressive to each other in confined tanks (SF, FishBase); keep females in the majority.
What fish can live with a Swordtail?
Species that passed every check include Neon Tetra, Cardinal Tetra, Harlequin Rasbora, Ember Tetra, Chili Rasbora, Celestial Pearl Danio.
Gear for a Swordtail setup
TankSmallest standard tank that meets its minimum: 55 gallon (48 in long).Find on Amazon →HeaterAbout 300 W for 55 gallons, holding 61–82°F.Find on Amazon →LidIt jumps. A full lid keeps it in the tank.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 →
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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/xiphophorus-hellerii/
- fishbase.se /summary/Xiphophorus-hellerii.html
- fishkeepingworld.com /swordtail/