Aquariumrainbowfish · freshwater
Forktail Blue-eye: adult size, tank size & tankmates
The Forktail Blue-eye (Pseudomugil furcatus) grows to about 2.8 in (6 cm SL). It needs a tank at least 24 inches long and about 14 gallons. Keep at least 8 together, at 75–82°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
- 2.8 in (6 cm SL)
- Minimum tank
- 24 inches long and about 14 gallons
- Temperature
- 75–82°F
- pH
- 7–8
- Hardness
- 15–30 dGH
- Group size
- 8+
- 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: may eat baby shrimp · jumps, so keep a lid
Forktail Blue-eye 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
- 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
- Glowlight TetraAdult ~1.9 in · 75–82°F
- GuppyAdult ~2.8 in · 63–82°F
- PlatyAdult ~2.4 in · 68–79°F
- Endler's LivebearerNeeds careAdult ~1.2 in · 75–86°F
- Honey GouramiAdult ~2.6 in · 72–81°F
- Dwarf GouramiNeeds careAdult ~4.2 in · 72–81°F
- Pearl GouramiAdult ~5.7 in · 75–86°F
Use caution
- Neon TetraForktail Blue-eye (15–30 dGH) and Neon Tetra (1–12 dGH) prefer different water hardness.
- Cardinal TetraForktail Blue-eye (15–30 dGH) and Cardinal Tetra (1–12 dGH) prefer different water hardness.
- Harlequin RasboraForktail Blue-eye (15–30 dGH) and Harlequin Rasbora (1–12 dGH) prefer different water hardness.
- Ember TetraForktail Blue-eye (15–30 dGH) and Ember Tetra (1–10 dGH) prefer different water hardness.
- Chili RasboraForktail Blue-eye (15–30 dGH) and Chili Rasbora (1–10 dGH) prefer different water hardness.
- Black Neon TetraForktail Blue-eye (15–30 dGH) and Black Neon Tetra (1–12 dGH) prefer different water hardness.
- Lemon TetraForktail Blue-eye (15–30 dGH) and Lemon Tetra (1–12 dGH) prefer different water hardness.
- German Blue RamNeeds careForktail Blue-eye and German Blue Ram only share 81–82°F. That's a tight window.
Avoid
- White Cloud Mountain MinnowNeeds careForktail Blue-eye (75–82°F) and White Cloud Mountain Minnow (57–72°F) need different temperatures.
- Chinese Algae EaterOutgrows tanksChinese Algae Eater grows 5× longer than Forktail Blue-eye and may treat it as food.
- Convict CichlidNeeds careConvict Cichlid is aggressive toward tankmates. Forktail Blue-eye is peaceful.
- Fancy GoldfishOutgrows tanksForktail Blue-eye (75–82°F) and Fancy Goldfish (50–70°F) need different temperatures.
- Iridescent SharkOutgrows tanksIridescent Shark eats small fish, and Forktail Blue-eye only grows to about 2.8 in.
- OscarOutgrows tanksOscar eats small fish, and Forktail Blue-eye only grows to about 2.8 in.
- Paradise FishNeeds careForktail Blue-eye (75–82°F) and Paradise Fish (50–72°F) need different temperatures.
- Weather LoachOutgrows tanksForktail Blue-eye (75–82°F) and Weather Loach (64–74°F) need different temperatures.
All 105 species we checked against the Forktail Blue-eye
| Species | Verdict | Why |
|---|---|---|
| African Dwarf Frog | Compatible | No conflicts found |
| Assassin Snail | Compatible | No conflicts found |
| Bala Shark | Compatible | No conflicts found |
| Betta | Compatible | No conflicts found |
| Black Skirt Tetra | 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 |
| Celestial Pearl Danio | Compatible | No conflicts found |
| Cherry Barb | Compatible | No conflicts found |
| Clown Pleco | Compatible | No conflicts found |
| Common Pleco | Compatible | No conflicts found |
| Congo Tetra | Compatible | No conflicts found |
| Denison Barb | Compatible | No conflicts found |
| Dwarf Gourami | Compatible | No conflicts found |
| Dwarf Neon Rainbowfish | Compatible | No conflicts found |
| Endler's Livebearer | Compatible | No conflicts found |
| Giant Danio | Compatible | No conflicts found |
| Glowlight Tetra | Compatible | No conflicts found |
| Guppy | Compatible | No conflicts found |
| Head-and-tail-light Tetra | Compatible | No conflicts found |
| Honey Gourami | Compatible | No conflicts found |
| Japanese Trapdoor Snail | Compatible | No conflicts found |
| Malaysian Trumpet Snail | Compatible | No conflicts found |
| Molly | Compatible | No conflicts found |
| Moonlight Gourami | Compatible | No conflicts found |
| Odessa Barb | 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 |
| Platy | Compatible | No conflicts found |
| Pristella Tetra | Compatible | No conflicts found |
| Ramshorn Snail | Compatible | No conflicts found |
| Rummy-nose Tetra | Compatible | No conflicts found |
| Serpae Tetra | Compatible | No conflicts found |
| Siamese Algae Eater | Compatible | No conflicts found |
| Silver Tip Tetra | Compatible | No conflicts found |
| Sterbai Cory | Compatible | No conflicts found |
| Swordtail | Compatible | No conflicts found |
| Tiger Barb | Compatible | No conflicts found |
| Upside-down Catfish | Compatible | No conflicts found |
| Variatus Platy | Compatible | No conflicts found |
| Zebra Danio | Compatible | No conflicts found |
| Amano Shrimp | Caution | Forktail Blue-eye may eat baby Amano Shrimp. Adults are usually safe, but expect fewer shrimplets. |
| Angelfish | Caution | Angelfish can bully smaller, peaceful Forktail Blue-eye. |
| Bamboo Shrimp | Caution | Forktail Blue-eye may eat baby Bamboo Shrimp. Adults are usually safe, but expect fewer shrimplets.; Forktail Blue-eye (15–30 dGH) and Bamboo Shrimp (6–10 dGH) prefer different water hardness. |
| Black Neon Tetra | Caution | Forktail Blue-eye (15–30 dGH) and Black Neon Tetra (1–12 dGH) prefer different water hardness. |
| Bleeding Heart Tetra | Caution | Forktail Blue-eye (15–30 dGH) and Bleeding Heart Tetra (1–12 dGH) prefer different water hardness. |
| Blood Parrot Cichlid | Caution | Blood Parrot Cichlid can bully smaller, peaceful Forktail Blue-eye. |
| Boesemani Rainbowfish | Caution | Forktail Blue-eye and Boesemani Rainbowfish only share 81–82°F. That's a tight window. |
| Bolivian Ram | Caution | Forktail Blue-eye (15–30 dGH) and Bolivian Ram (1–10 dGH) prefer different water hardness. |
| Cardinal Tetra | Caution | Forktail Blue-eye (15–30 dGH) and Cardinal Tetra (1–12 dGH) prefer different water hardness. |
| Cherry Shrimp | Caution | Forktail Blue-eye may eat baby Cherry Shrimp. Adults are usually safe, but expect fewer shrimplets.; Forktail Blue-eye (15–30 dGH) and Cherry Shrimp (6–14 dGH) prefer different water hardness. |
| Chili Rasbora | Caution | Forktail Blue-eye (15–30 dGH) and Chili Rasbora (1–10 dGH) prefer different water hardness. |
| Clown Killifish | Caution | Forktail Blue-eye (15–30 dGH) and Clown Killifish (1–8 dGH) prefer different water hardness. |
| Clown Loach | Caution | Forktail Blue-eye (15–30 dGH) and Clown Loach (1–12 dGH) prefer different water hardness. |
| Cockatoo Dwarf Cichlid | Caution | Forktail Blue-eye (pH 7–8) and Cockatoo Dwarf Cichlid (pH 5–6) prefer different pH. |
| Common / Comet Goldfish | Caution | Forktail Blue-eye and Common / Comet Goldfish only share 75–75°F. That's a tight window. |
| Crystal Red Shrimp | Caution | Forktail Blue-eye and Crystal Red Shrimp only share 75–76°F. That's a tight window.; Forktail Blue-eye may eat baby Crystal Red Shrimp. Adults are usually safe, but expect fewer shrimplets. |
| Diamond Tetra | Caution | Forktail Blue-eye (15–30 dGH) and Diamond Tetra (5–12 dGH) prefer different water hardness. |
| Discus | Caution | Forktail Blue-eye (15–30 dGH) and Discus (0–5 dGH) prefer different water hardness. |
| Electric Blue Acara | Caution | Electric Blue Acara can bully smaller, peaceful Forktail Blue-eye. |
| Electric Yellow Lab | Caution | Electric Yellow Lab can bully smaller, peaceful Forktail Blue-eye. |
| Ember Tetra | Caution | Forktail Blue-eye (15–30 dGH) and Ember Tetra (1–10 dGH) prefer different water hardness. |
| Firemouth Cichlid | Caution | Firemouth Cichlid can bully smaller, peaceful Forktail Blue-eye. |
| German Blue Ram | Caution | Forktail Blue-eye and German Blue Ram only share 81–82°F. That's a tight window.; Forktail Blue-eye (15–30 dGH) and German Blue Ram (1–10 dGH) prefer different water hardness. |
| Ghost Shrimp | Caution | Forktail Blue-eye may eat baby Ghost Shrimp. Adults are usually safe, but expect fewer shrimplets. |
| Glass Catfish | Caution | Forktail Blue-eye (15–30 dGH) and Glass Catfish (1–10 dGH) prefer different water hardness. |
| Gold Barb | Caution | Forktail Blue-eye and Gold Barb only share 75–75°F. That's a tight window. |
| Harlequin Rasbora | Caution | Forktail Blue-eye (15–30 dGH) and Harlequin Rasbora (1–12 dGH) prefer different water hardness. |
| Hillstream Loach | Caution | Forktail Blue-eye and Hillstream Loach only share 75–75°F. That's a tight window.; Forktail Blue-eye (15–30 dGH) and Hillstream Loach (1–10 dGH) prefer different water hardness. |
| Julii Cory | Caution | Forktail Blue-eye (15–30 dGH) and Julii Cory (1–12 dGH) prefer different water hardness. |
| Kissing Gourami | Caution | Kissing Gourami grows 4× longer than Forktail Blue-eye and may treat it as food.; Kissing Gourami can bully smaller, peaceful Forktail Blue-eye. |
| Kribensis | Caution | Forktail Blue-eye (15–30 dGH) and Kribensis (0–12 dGH) prefer different water hardness. |
| Kuhli Loach | Caution | Forktail Blue-eye (15–30 dGH) and Kuhli Loach (0–8 dGH) prefer different water hardness. |
| Lambchop Rasbora | Caution | Forktail Blue-eye (15–30 dGH) and Lambchop Rasbora (1–10 dGH) prefer different water hardness. |
| Lemon Tetra | Caution | Forktail Blue-eye (15–30 dGH) and Lemon Tetra (1–12 dGH) prefer different water hardness. |
| Marbled Hatchetfish | Caution | Forktail Blue-eye (15–30 dGH) and Marbled Hatchetfish (1–10 dGH) prefer different water hardness. |
| Mystery Snail | Caution | Forktail Blue-eye (pH 7–8) and Mystery Snail (pH unknown) prefer different pH.; Forktail Blue-eye (15–30 dGH) and Mystery Snail (unknown dGH) prefer different water hardness. |
| Neon Tetra | Caution | Forktail Blue-eye (15–30 dGH) and Neon Tetra (1–12 dGH) prefer different water hardness. |
| Nerite Snail | Caution | Forktail Blue-eye (15–30 dGH) and Nerite Snail (6–12 dGH) prefer different water hardness. |
| Otocinclus | Caution | Forktail Blue-eye (15–30 dGH) and Otocinclus (1–12 dGH) prefer different water hardness. |
| Panda Cory | Caution | Forktail Blue-eye (15–30 dGH) and Panda Cory (1–12 dGH) prefer different water hardness. |
| Peppered Cory | Caution | Forktail Blue-eye (15–30 dGH) and Peppered Cory (0–12 dGH) prefer different water hardness. |
| Pictus Catfish | Caution | Pictus Catfish can bully smaller, peaceful Forktail Blue-eye.; Forktail Blue-eye (pH 7–8) and Pictus Catfish (pH 5.8–6.8) prefer different pH. |
| Pygmy Cory | Caution | Forktail Blue-eye (15–30 dGH) and Pygmy Cory (0–8 dGH) prefer different water hardness. |
| Rainbow Shark | Caution | Rainbow Shark can bully smaller, peaceful Forktail Blue-eye. |
| Red-Tail Shark | Caution | Red-Tail Shark can bully smaller, peaceful Forktail Blue-eye. |
| Rosy Barb | Caution | Forktail Blue-eye and Rosy Barb only share 75–75°F. That's a tight window. |
| Scissortail Rasbora | Caution | Forktail Blue-eye (15–30 dGH) and Scissortail Rasbora (2–12 dGH) prefer different water hardness. |
| Silver Hatchetfish | Caution | Forktail Blue-eye (15–30 dGH) and Silver Hatchetfish (1–12 dGH) prefer different water hardness. |
| Sparkling Gourami | Caution | Forktail Blue-eye (15–30 dGH) and Sparkling Gourami (1–12 dGH) prefer different water hardness. |
| Three-spot Gourami | Caution | Three-spot Gourami can bully smaller, peaceful Forktail Blue-eye. |
| Tinfoil Barb | Caution | Forktail Blue-eye (15–30 dGH) and Tinfoil Barb (2–10 dGH) prefer different water hardness. |
| Yoyo Loach | Caution | Yoyo Loach can bully smaller, peaceful Forktail Blue-eye.; Forktail Blue-eye (15–30 dGH) and Yoyo Loach (2–12 dGH) prefer different water hardness. |
| Chinese Algae Eater | Avoid | Chinese Algae Eater grows 5× longer than Forktail Blue-eye and may treat it as food.; Chinese Algae Eater is aggressive toward tankmates. Forktail Blue-eye is peaceful. |
| Convict Cichlid | Avoid | Convict Cichlid is aggressive toward tankmates. Forktail Blue-eye is peaceful. |
| Fancy Goldfish | Avoid | Forktail Blue-eye (75–82°F) and Fancy Goldfish (50–70°F) need different temperatures. |
| Iridescent Shark | Avoid | Iridescent Shark eats small fish, and Forktail Blue-eye only grows to about 2.8 in. |
| Oscar | Avoid | Oscar eats small fish, and Forktail Blue-eye only grows to about 2.8 in. |
| Paradise Fish | Avoid | Forktail Blue-eye (75–82°F) and Paradise Fish (50–72°F) need different temperatures. |
| Weather Loach | Avoid | Forktail Blue-eye (75–82°F) and Weather Loach (64–74°F) need different temperatures.; Forktail Blue-eye (15–30 dGH) and Weather Loach (1–12 dGH) prefer different water hardness. |
| White Cloud Mountain Minnow | Avoid | Forktail Blue-eye (75–82°F) and White Cloud Mountain Minnow (57–72°F) need different temperatures. |
Care notes
Needs: Densely planted tank with some floating plants, well-oxygenated water with some flow; prefers small live foods (Daphnia, Moina, Artemia nauplii) but takes small dry food; secure lid
Group: SF: shoaling; keep at least 8-10; males spar and display but rarely harm each other
Temperament: peaceful toward other fish, peaceful toward its own kind. Lives in the middle of the tank.
Common questions
How big does a Forktail Blue-eye get?
About 2.8 inches (6 cm SL) as an adult, according to seriouslyfish.com.
What size tank does a Forktail Blue-eye need?
At least 24 inches long and about 14 gallons. The smallest standard tank that meets that is a 20 gallon long.
How many Forktail Blue-eyes should be kept together?
At least 8. SF: shoaling; keep at least 8-10; males spar and display but rarely harm each other
What fish can live with a Forktail Blue-eye?
Species that passed every check include Celestial Pearl Danio, Cherry Barb, Rummy-nose Tetra, Glowlight Tetra, Guppy, Platy.
Gear for a Forktail Blue-eye setup
TankSmallest standard tank that meets its minimum: 20 gallon long (30 in long).Find on Amazon →HeaterAbout 100 W for 20 gallons, holding 75–82°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/pseudomugil-furcatus/
- fishbase.se /summary/Pseudomugil-furcatus.html
- aquariumsource.com /forktail-rainbowfish/