Best Tank Mates for Rummy-Nose Tetra: Compatible Fish and Species to Avoid
The best rummy-nose tetra tank mates are small, peaceful fish that like the same warm, soft water: cardinal, black neon and ember tetras, harlequin rasboras, Corydoras, otocinclus, hatchetfish, pencilfish, and, in the right setup, dwarf cichlids or discus. Skip fin-nippers, anything big enough to swallow a 2-inch fish, and cool-water species. Below is a vetted shortlist organized by tank zone and tank size, plus the species that show up on generic lists but don't actually fit.
Know Your Rummy-Nose First
Three different fish are sold as "rummy-nose tetra":
- True rummy-nose (Hemigrammus rhodostomus)
- False rummy-nose (Hemigrammus bleheri), the one most often found in US stores
- Petitella georgiae, also sold under the rummy-nose name
They look nearly identical to most buyers, and the compatibility advice in this guide applies to all three.
| Trait | What to plan for |
|---|---|
| Adult size | About 2 in (5 cm) |
| Lifespan | Roughly 5–8 years with good care |
| Temperature | 75–82°F (24–28°C) for most setups; tolerates up to about 84°F (29°C) |
| pH | 5.5–7.0 |
| Hardness | Soft to moderately soft, roughly 2–12 dGH |
| Group size | 6 minimum; 8–12 or more is better |
| Tank | 20-gallon long (76 L) minimum for the school; 29–40 gal (110–150 L) for mates |
Rummies are among the tightest-schooling tetras. A big group swims boldly in the open, holds its formation and shows its best color; a group of three or four tends to hide and scatter. A long footprint beats a tall tank because these fish use horizontal swimming space.
The Three Filters That Decide Compatibility
Most tank mate lists judge fish on a "peaceful" label alone. For rummies, three questions matter more:
- Does its water window overlap? A good mate must be comfortable in warm, soft, slightly acidic water, especially at the warm end (78–82°F / 26–28°C).
- Is it calm? No fin-nipping, chasing or feeding-time bullying.
- Mouth size and speed. It shouldn't be able to swallow a 2-inch fish, and it shouldn't be so fast and boisterous that it grabs all the food.
Run every candidate through all three before you buy.
Plan by Tank Zone
Rummies live in mid-water. The easiest way to build a balanced community is to fill the other levels with different fish and add only one or two other calm mid-water schools.
Midwater Schooling Fish
This is the zone where competition and clashes happen, so choose carefully. The best calm mid-water partners are:
- Cardinal tetras: same soft, warm water; a natural pairing.
- Harlequin rasboras and lambchop rasboras: gentle, colorful, and comfortable in soft water.
- Ember tetras: tiny, orange and peaceful.
- Glowlight tetras: calm and hardy.
- Neon and black neon tetras (more below).
Avoid serpae-type tetras despite their popularity. They nip fins and stress tight schools.
Bottom Dwellers
- Corydoras: sterbai cories tolerate warmth especially well.
- Otocinclus: small, peaceful algae grazers.
- Bristlenose pleco or other small plecos.
- Kuhli loaches: nocturnal and shy; they appreciate soft sand and cover.
Browse Corydoras on FishyHub if you want a warm-tolerant bottom crew.
Top Dwellers
- Hatchetfish: surface skimmers that stay out of the rummies' way (keep a lid on).
- Pencilfish: slim, peaceful and soft-water lovers.
Centerpiece Fish
- Honey or dwarf gourami: one calm focal fish for 20–40 gallons.
- Bolivian ram or Apistogramma: good in larger tanks with caves and plants.
- Discus: a classic pairing in a warm, big, soft-water setup; rummies are a traditional dither fish for discus.
Best Schooling Aquarium Fish to Pair With Rummies
Ranked roughly by how well they overlap the warm end of the rummy range. Most need a group of 6 or more to behave naturally.
| Species | Adult size | Warm-water overlap | Notes |
|---|---|---|---|
| Cardinal tetra | small | Excellent | Soft-water natural partner; wild neighbor |
| Black neon tetra | ~1.5 in | Very good | Hardy, peaceful, loves plants |
| Ember tetra | <1 in | Very good | Tiny; best in calm planted tanks |
| Harlequin / lambchop rasbora | ~1.5–2 in | Good | Gentle mid-water schoolers |
| Glowlight tetra | ~1.5 in | Good | Calm, easy |
| Pristella (X-ray) tetra | ~2 in | Good | Broad tolerance; budget pick |
| Neon tetra | ~1.5 in | Good | Peaceful classic; schools with its own kind |
| Colombian tetra (H. columbianus) | ~2.5 in | Fair | Fast; 30+ gal; no long fins |
| Boehlkea (Cochu's blue) tetra | ~2 in | Fair | Tops out around 79°F; keep 8+ |
Neon and cardinal tetras can share a tank with rummies, but expect each species to school mostly with its own kind.
Species Spotlights
Black Neon Tetra
Hyphessobrycon herbertaxelrodi reaches about 1.5 in (4 cm), is very hardy and peaceful, and does best in a school of 6 or more in a planted tank. It is a top-tier companion: the black-and-white stripe contrasts nicely with the rummies' red heads.
Pristella (X-ray) Tetra
About 2 in (5 cm), hardy, and tolerant of a broader range of water than rummies. It is peaceful in groups of 6+, though it can turn skittish around large fish. A good, budget-friendly companion for a community tank.
Boehlkea (Cochu's Blue) Tetra
A blue-bodied fish with a red tail, about 2 in (5 cm), preferring 72–79°F (22–26°C) and pH 6–7. Reports on its behavior disagree: some keepers call it peaceful, others find it territorial or nippy. Small groups tend to be pushy. Treat it as a conditional pick: only in groups of 8 or more, only in 30+ gallons (114+ L), and keep the tank at the cooler end of the rummy range. Watch for chasing in the first weeks.
Colombian Tetra (Hyphessobrycon columbianus)
Also called the blue-red tetra, it grows to about 2.5 in (6 cm) and prefers 71–83°F (22–28°C) and pH 6.5–7.5. It has a nipper reputation, yet many keepers report peaceful behavior. It is fast and active, which suits speedy schoolers like rummies, but it is a poor choice alongside slow, long-finned fish. Give it 30+ gallons and a tight lid, because it jumps.
Half-Red Hemigrammus (Collector Option)
A rare, possibly undescribed Venezuelan fish close to H. stictus, only 1–1.4 in (2.5–3.5 cm). It has been collected in water around 83°F (28°C) and pH near 5.2, which makes it conceptually an ideal warm, soft-water mate. It is a niche find for collectors rather than something you'll see every week.
A Soft-Water Amazon Biotope Option
In the wild, rummies occur in Rio Negro tributaries alongside cardinal tetras, pencilfish, checkerboard cichlids and Apistogramma. A biotope-style tank recreates that: soft, acidic water, sand, driftwood, leaf litter and dim light. Wild schools are also looser than the tight formations seen in aquariums, so don't worry if a relaxed school spreads out a little.
Stocking Plans by Tank Size
These sample combos assume a cycled, planted tank with good filtration. Adjust downward if your tank is lightly filtered.
| Tank | Rummy school | Sample mates |
|---|---|---|
| 20 gal long (76 L) | 8–10 | 6 sterbai cories or 5 otocinclus; optional small group of embers |
| 29 gal (110 L) | 10–12 | 6 cories, 8 black neons or harlequins, 1 honey gourami |
| 40 gal breeder (150 L) | 12+ | 8 cardinals, 6 cories, 6 hatchetfish or pencilfish, a pair of Bolivian rams or Apistogramma, 1 bristlenose |
| 55+ gal (208+ L) | 15+ | Large rummy and cardinal schools, cories, kuhli loaches; or a warm discus setup with rummies as dither fish |
Guides disagree on minimum size (anywhere from 15 to 20+ gallons). A 20-gallon long is the realistic minimum just for the school; mates need more room.
Fish That Need Caution
Livebearers (Guppies, Platies, Swordtails, Mollies)
Some lists include livebearers freely, but they prefer harder, more alkaline water than rummies. Guppies, platies or swordtails can work only in a neutral, moderately hard tap-water tank. Skip mollies, which like different conditions and tolerate brackish water. None of them belong in a soft blackwater setup.
Angelfish
Adult angelfish can eat 2-inch tetras. The pairing is possible if both grow up together in a large tank, but it remains a risk.
Discus
A proven pairing, with a catch: discus are kept warm, and rummies cope best at the lower end of discus temperatures (82–84°F / 28–29°C). Keep the water pristine and it works well.
Bettas
Sometimes workable in 20+ gallons. Rummies are fast and not nippy, so the outcome depends on the individual betta's temperament.
Species to Avoid
- Predators with big mouths: oscars, large cichlids, arowanas, and in some cases adult angelfish.
- Fin-nippers and bullies: tiger barbs, serpae tetras, and Boehlkea tetras kept in small groups.
- Boisterous larger fish: bigger danios can outcompete rummies at feeding time.
- Cold-water species: goldfish and white cloud minnows. Some rainbowfish also appear on generic lists, but their preferred ranges barely overlap; leave them out.
Invertebrates
- Nerite and mystery snails: fine.
- Amano shrimp: fine; large enough to be ignored.
- Cherry shrimp: adults are usually left alone, but shrimplets will be eaten, so don't expect a colony to grow.
The Nose Test: A Built-In Stress Gauge
A rummy's red head is a live readout of how it feels. After each new addition, check the noses over the next few days. A pale nose signals stress from bullying, poor water quality or new-tank problems. If the color fades after you add a fish, that fish is the first suspect.
Adding Tank Mates the Right Way
- Cycle first. Add rummies only to a fully cycled tank, and let them settle before adding mates.
- Quarantine new fish for 2–4 weeks in a separate tank with a sponge filter, watching for disease and feeding problems.
- Add peaceful schoolers in groups, not one or two at a time.
- Add centerpiece fish last, so they can't claim the whole tank before everyone else is established.
- Set up for low stress: live plants, driftwood, leaf litter, subdued lighting and open swimming lanes help every fish in the tank.
Feeding a Mixed-Level Community
Rummies and other tetras eat fast at the surface and mid-water. Bottom fish like cories, loaches and otos can go hungry. Target-feed sinking foods (pellets, wafers or a gel food) near the bottom, ideally after lights-out for kuhlis, and give the tetras a small portion first to keep them busy.
Common Mistakes and Troubleshooting
- Adding rummies to an uncycled or brand-new tank. They are sensitive to ammonia, nitrite and parameter swings.
- Buying only 3–4. Small groups hide, lose color and scatter.
- Picking by "peaceful" label alone while ignoring temperature and pH overlap.
- Adding fin-nippers or a lone aggressive cichlid. Watch for torn fins and pale noses.
- Expecting tiny shrimp or fry to survive alongside tetras.
- Letting fast eaters starve slow or bottom fish. Target-feed.
Troubleshooting:
- Faded nose: test ammonia, nitrite and nitrate, watch for a bully, and reduce stress with cover and stable conditions.
- Fish hiding: increase the school size, add plants and dim the lighting.
Frequently Asked Questions
How many rummy-nose tetras should I keep?
Keep at least 6, and ideally 10 or more. Larger schools swim more boldly, hold a tighter formation and show stronger color. Small groups tend to hide and look washed out.
Can rummy-nose tetras live with bettas?
Sometimes, in a tank of 20 gallons or more. Rummies are fast and don't nip, so they rarely bother a betta. Whether it works depends on the betta, since some individuals chase every fish in the tank.
Can rummy-nose tetras live with angelfish or discus?
Angelfish are risky because adults may eat 2-inch tetras, though fish raised together in a large tank can coexist. Discus are a classic match if you keep the water around 82–84°F (28–29°C), soft and very clean.
Will rummy-nose tetras school with neon or cardinal tetras?
They get along well and can share a tank without trouble. Each species will generally school with its own kind, so buy a proper group of each.
Can I keep shrimp or guppies with rummy-nose tetras?
Amano shrimp are a safe choice, while cherry shrimp colonies will lose their babies to the tetras. Guppies only suit a neutral, moderately hard water tank and aren't ideal in the soft water rummies prefer.
Why is my rummy-nose tetra's nose pale?
A pale nose points to stress: poor water quality, new-tank problems, or a bully in the tank. Test your water first, then watch the tank for chasing, especially if you recently added a fish.
Build Your Rummy Community
Start with a proper school, then add bottom and top dwellers that share the warm, soft water, and use the nose test after each addition. When you're ready to pick companions, browse the tetra selection or the full range of small community fishes on FishyHub.
