Rosy tetra care guide
Also called: Rosy-finned tetra, White-finned rosy tetra, Rosaceus tetra
The rosy tetra is a peaceful South American tetra with a pinkish body and a black-and-white tipped dorsal fin. Keep six or more in a calm, well-planted 20-gallon (76 L) tank with soft, slightly acidic water for the best color.
Rosy tetras need a tank of at least 20 gallons (76 L), a group of 6 or more, and water at 24–28°C (75–82°F) with a pH of 5.5–7.5. They grow to about 4 cm (1.6 in) and are peaceful.
Plan a tank with rosy tetrasSee all tank mates
Rosy tetra quick facts
| Scientific name | Megalamphodus rosaceus |
|---|---|
| Family | Acestrorhamphidae |
| Origin | Essequibo, Corantijn and Suriname river basins in Guyana, Suriname and northern Brazil |
| Adult size | 4 cm (1.6 in) |
| Minimum tank | 20 gallons (76 L), at least 60 cm (24 in) long |
| Temperature | 24–28°C (75–82°F) |
| pH | 5.5–7.5 |
| Hardness (GH) | 2–12 dGH |
| Group size | 6 or more (shoaling fish) |
| Temperament | Peaceful |
| Swims at | Middle |
| Diet | Omnivore |
| Care level | Moderate |
| Lifespan | 4–6 years |
| Safe with shrimp? | Mostly (eats baby shrimp) |
| Safe with plants? | Yes |
Tank setup
A group of six needs at least a 20-gallon (76 L) tank about 60 cm (24 in) long. Plant it heavily and add wood and floating plants for shade. In bare, bright tanks they turn pale and shy.
How many rosy tetras in a tank?
The smallest common tank that suits rosy tetras is a 20 gallon. Here is roughly how many fit in each size when they are the only fish, based on adult size and waste output. Leave room if you want tank mates.
| Tank | Rosy tetras (alone) |
|---|---|
| 3 gallon | Too small |
| 5 gallon | Too small |
| 10 gallon | Too small |
| 15 gallon | Too small |
| 20 gallon | 6–27 |
| 20 gallon long | 6–27 |
| 29 gallon | 6–39 |
| 40 gallon | 6–54 |
| 55 gallon | 6–74 |
| 75 gallon | 6–102 |
| 125 gallon | 6–170 |
What you need for rosy tetras
Sized for a 20 gallon tank, the smallest common size that suits a group of 6 rosy tetras. For a different tank or a mix of fish, use the stocking calculator for a list sized to your plan.
Tank and equipment
- 20 gallon aquarium (tank or kit) (opens Amazon in a new tab)Bigger tanks are more stable and easier for beginners. How to choose
- Aquarium stand for 20 gallons (opens Amazon in a new tab)The water alone weighs about 167 lb (76 kg), before glass, gravel and rock. How to choose
- Adjustable heater, 75 W (opens Amazon in a new tab)Holds about 79 °F (26 °C) in a room at 65 °F (18 °C). How to choose
- Aquarium thermometer (opens Amazon in a new tab)Check it daily: heaters can fail stuck on or off. How to choose
- Hang-on-back filter rated 80–120 GPH (opens Amazon in a new tab)Community tank: 4–6 times the tank volume per hour. How to choose
- About 35 lb of aquarium gravel (opens Amazon in a new tab)Enough for a layer about 2 in (5 cm) deep. Smooth gravel suits most community fish. How to choose
- Water conditioner (dechlorinator) (opens Amazon in a new tab)Removes chlorine and chloramine from tap water. Seachem Prime is a popular, concentrated choice. How to choose
- Liquid test kit (ammonia, nitrite, nitrate, pH) (opens Amazon in a new tab)Liquid kits are more accurate than strips. The API Freshwater Master Test Kit is the common choice. How to choose
- Gravel vacuum (siphon) (opens Amazon in a new tab)Cleans the gravel and does the water change in one go. How to choose
- LED aquarium light, about 24 in long (opens Amazon in a new tab)Match the light to the tank length. Basic LEDs grow easy plants. How to choose
Food and extras for rosy tetras
- Micro pellets or flakes for small fish (opens Amazon in a new tab)Small enough for tetras, rasboras and other nano fish.
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Water parameters
Keep them at 24–28 °C (75–82 °F), pH 5.5–7.5 and soft water of 2–12 dGH. Colors are strongest in soft, slightly acidic water. They need clean, stable water, so make regular small water changes rather than rare big ones.
Best tank mates for rosy tetras
These popular species share rosy tetras' water needs and temperament. See the full list of 84 good matches.
Betta fish
6.5 cm (2.6 in) · 24–28°C (75–82°F)
Cherry shrimp
3 cm (1.2 in) · 20–27°C (68–81°F)
Nerite snail
2.5 cm (1 in) · 22–27°C (72–81°F)
Guppy
5 cm (2 in) · 22–27°C (72–81°F)
Dwarf gourami
7.5 cm (3 in) · 24–28°C (75–82°F)
Bristlenose pleco
12 cm (4.7 in) · 22–26°C (72–79°F)
Bronze corydoras
7 cm (2.8 in) · 21–26°C (70–79°F)
Assassin snail
2.5 cm (1 in) · 22–27°C (72–81°F)
Avoid keeping rosy tetras with
- Angelfish: Angelfish can eat rosy tetras: they're small enough to fit in its mouth once it's grown.
- Common goldfish: They need different temperatures: Rosy tetra 24–28°C (75–82°F), common goldfish 15–22°C (59–72°F).
- Fancy goldfish: They need different temperatures: Rosy tetra 24–28°C (75–82°F), fancy goldfish 18–23°C (64–73°F).
- Oscar: Oscar can eat rosy tetras: they're small enough to fit in its mouth once it's grown.
- Bala shark: Bala shark can eat rosy tetras: they're small enough to fit in its mouth once it's grown.
- Chinese algae eater: Chinese algae eater is aggressive and will bully or injure peaceful rosy tetras.
Feeding
They eat small invertebrates in the wild and accept most foods in the tank. Feed a good flake or micro pellet and add frozen or live bloodworm, brine shrimp and daphnia. Give small meals once or twice a day.
Behavior
Very peaceful and a little timid. Males flare their fins at each other in displays that rarely cause harm. Boisterous or nippy fish stress them and target the males' tall dorsal fins. Good tankmates include small tetras, hatchetfish, pencilfish, corydoras and dwarf cichlids.
Breeding
Possible but harder than with many tetras. Use a small, dim spawning tank with very soft, acidic water, java moss or a spawning mop, and a gentle sponge filter. Remove the adults once eggs appear. Eggs hatch in 24–36 hours, and the fry need infusoria before they can take baby brine shrimp.
Tips from experienced keepers
- Males have a taller, sickle-shaped dorsal fin. Females are rounder with shorter fins.
- Do not keep them with serpae tetras, tiger barbs or other fin nippers.
- Dim light, floating plants and a dark substrate bring out the rosy color.
- The look-alike bentosi (ornate) tetra has a dark mark behind the gill cover. The rosy tetra does not.
- Acclimate slowly. They dislike sudden changes in water chemistry.
Frequently asked questions
Are rosy tetras fin nippers?
No. Rosy tetras are peaceful and are more likely to be nipped than to nip. Keep them away from serpae tetras, tiger barbs and other nippy fish.
How many rosy tetras should I keep?
At least six, and ten or more if you have room. Larger groups are bolder and show more of the males' fin displays.
What is the difference between a rosy tetra and a bentosi tetra?
They look very similar and are often mixed up in shops. The bentosi (ornate) tetra has a dark mark just behind the gill cover, while the rosy tetra lacks it. Their care is almost the same.
Sources
We checked these references when writing this page. Values are for healthy long-term keeping, not survival limits. Last reviewed 2026-10-13. See our editorial policy.