Rummy-Nose Tetra Care Guide: Tank Size, Diet, Water Parameters and Temperament

Rummy-nose tetras do best in a 20-gallon long or larger, cycled tank at 75–82°F (24–28°C), in soft to moderately soft water (pH 6.0–7.0), kept in a school of 8–12. They are peaceful mid-water omnivores that eat flakes, micro-pellets and small frozen foods. Their bright red head doubles as a live readout of water quality: when the red fades, something in the tank needs attention.

Quick Facts

Trait	Recommendation
Adult size	About 2 in (5 cm), up to 2.5 in (6.4 cm)
Lifespan	5–6 years typical; up to 8 in very stable tanks
Minimum tank	20-gallon long (76 L); 29–40 gallons (110–150 L) is easier
Group size	8–12 ideal; 6 absolute minimum
Temperature	75–82°F (24–28°C); target about 78°F (26°C)
pH	6.0–7.0 preferred; tolerates about 5.5–7.5 once settled
Hardness	GH 2–8 dGH, KH 2–6 dKH
Ammonia / nitrite / nitrate	0 / 0 / under 20 ppm
Diet	Omnivore, mid-water feeder
Temperament	Peaceful, non-nippy, excellent schooler
Care level	Easy-intermediate: hardy once settled, fragile going in

Which Rummy-Nose Are You Buying?

Three closely related fish are sold under the same name. Care is nearly identical, but it helps to know what you have.

• True rummy-nose (Hemigrammus rhodostomus): red is mostly confined to the head.
• Brilliant or firehead rummy-nose (H. bleheri, now often placed in Petitella): the red runs past the gill cover onto the front of the body. This is the most vivid form and the one most commonly sold in the US.
• False rummy-nose (Petitella georgiae): a close look-alike; compare how far the red reaches and how the tail stripes are patterned to tell it apart.

All three share a silvery, slightly torpedo-shaped body and a black-and-white striped tail. The stripe pattern is a useful field mark when comparing fish side by side.

The Brilliant Rummy-Nose (H. bleheri)

The brilliant rummy comes from the Rio Negro and Rio Meta basins, where water is very soft and acidic. It does best at the soft end of the ranges above and is sensitive to copper, so avoid copper-based medications and check that plant fertilizers and additives are safe for sensitive fish.

Tank Size and Setup

A 20-gallon long is the practical minimum. Some keepers say 10 gallons is enough, but a 10-gallon cannot hold a proper school and swings in temperature and chemistry too easily; save it for breeding. A 29- or 40-gallon tank makes stability much easier.

Footprint matters more than height. Rummies cruise horizontally, so a long tank beats a tall one of the same volume. A lid is not critical, but it helps limit evaporation and the occasional startled jump.

A rough stocking guide is about 2 gallons per rummy-nose, before counting other fish.

Aquascape

• Substrate: sand or fine gravel, ideally dark, which makes the red and silver stand out.
• Plants: java fern, anubias, Amazon swords and crypts around the back and sides.
• Driftwood for structure and a mild tannin effect.
• Open mid-water swim lane down the middle so the school can move as a unit.
• Floating plants to soften the light.
• Leaf litter and other botanicals are optional but suit the fish well.

Filtration and Maintenance

Choose a filter with strong biological capacity and gentle to moderate flow: a sponge filter, a hang-on-back filter with a baffle, or a canister. Do 25–30% water changes weekly with dechlorinated, temperature-matched water. Skipped changes let nitrate creep upward, and rummies show it quickly.

Lighting

Use moderate or dimmed lighting. A bright light over a bare tank washes out color and keeps the fish on edge. Run an 8–10 hour photoperiod on a timer. Fish need a real dark period; 24-hour lighting stresses them and feeds algae. Moonlights are optional, but keep them dim and on for a short time only.

Water Parameters

Sources quote a wide spread of numbers. The most useful rule is that stability matters more than hitting an exact figure.

• Temperature: 75–82°F (24–28°C). About 78°F (26°C) suits most community tanks and makes rummies a good fit for warm setups with discus or rams.
• pH: 6.0–7.0 is ideal. Settled fish tolerate roughly 5.5–7.5.
• Hardness: GH 2–8 dGH, KH 2–6 dKH (soft to moderately hard).
• Nitrogen: ammonia and nitrite at 0 ppm, nitrate under 20 ppm.

Rummies react badly to ammonia or nitrite spikes. Only add them to a tank that is fully cycled and has been running for a while, ideally 2–3 months.

Working With US Tap Water

Many US municipal supplies are hard and alkaline. The good news is that most rummies sold in the US are tank-raised and adapt to moderate tap water as long as it stays stable. Don't chase numbers with pH-adjusting chemicals; the swings they cause do more harm than slightly hard water.

If your tap is very hard or you keep wild-type brilliant rummies, soften it gradually:

1. Blend RO or distilled water with tap water. Start with a partial mix and adjust based on test results.
2. Add peat or botanicals to the filter for gentle acidity.
3. Use driftwood, which releases tannins over time.
4. Test KH as you go. If KH drops too low, pH can crash suddenly. Make every change slowly, over several water changes.

Diet and Feeding

Rummy-nose tetras are omnivores that feed mid-water. Build the diet around:

• Quality micro-pellets or flakes as the daily base.
• Frozen or live baby brine shrimp and daphnia several times a week.
• Bloodworms as an occasional treat.
• Some plant matter, such as a flake with vegetable content.
• Color-enhancing foods containing krill or astaxanthin, which support the red head.

Feed two small meals a day and give only what the school finishes in about 2 minutes. Overfeeding is a common problem in smaller tanks because leftover food quickly becomes ammonia. You can browse flakes, pellets and freeze-dried options in the Food & Supplements section.

Temperament and Schooling

Rummies are peaceful and non-nippy. They stay mostly in the middle of the tank, sometimes the upper levels, and make excellent dither fish that encourage shy species to come out.

Group size changes everything. In a group of 8–12 or more, they swim in a tight, synchronized school that ranks among the best in the hobby. In small groups, they hide, lose color and scatter. Six is the floor; eight or more is the real recommendation.

Sample Stocking Plans

Tank	Rummy-noses	Suggested companions
20-gallon long (76 L)	8	5–6 pygmy or small corydoras, a few otocinclus or nerite snails
29 gallons (110 L)	10–12	6 corydoras, a pair of honey gouramis or a single calm male betta, shrimp colony
40 gallons (150 L)	12–15	8 harlequin rasboras or pencilfish, 6 corydoras, a pair of rams or apistogramma, a bristlenose pleco

Adjust down if your filtration is modest, and add fish in stages rather than all at once.

Tankmates

Good choices:

• Corydoras and otocinclus
• Small rasboras, such as harlequins
• Other small tetras: cardinals, neons, embers, lemons
• Pencilfish and hatchetfish
• Dwarf cichlids such as rams and apistogramma
• Pearl and honey gouramis
• Discus (a good temperature match)
• Bristlenose plecos
• Shrimp and snails (adults are safe; shrimplets may be eaten)

Bottom dwellers pair especially well; the corydoras selection is a good place to look.

Avoid or use caution:

• Large cichlids, which will eat them.
• Angelfish only with caution: small angels are fine, but large adults may prey on rummies.
• Known fin nippers.
• Fast, boisterous barbs that outcompete them at feeding time.

A Note on Bettas

A single male betta can share a 20-gallon or larger tank with rummies if the betta has a calm temperament. Rummies ignore betta accessories like leaf hammocks, and they are not fin nippers, which makes them one of the better tetra choices here. Watch the first few days and separate them if the betta starts chasing.

The Red Nose as a Health Gauge

A vivid red head means a comfortable fish. A faded or pale head signals stress. Paleness is normal for a few days after purchase and briefly at lights-on, but lasting fading deserves a check. Always test the water first.

What you see	Likely cause	What to do
Pale nose, new arrivals	Shipping and acclimation stress	Keep lights low, feed lightly, wait a few days
Pale nose after a water change	Temperature or chemistry swing	Match temperature and pH more closely next time
Pale nose, whole school	Ammonia, nitrite or high nitrate	Test, then do a water change
Pale nose, fish hiding	Bright light or bare tank	Dim lights, add plants and cover
One fish pale, torn fins	Bullying	Identify and remove the aggressor
Pale plus spots or clamped fins	Disease	Isolate and diagnose (see below)

Buying, Acclimation and Quarantine

When choosing fish, pick a school with bright red heads and full bellies. Skip groups with clamped fins, pinched stomachs or visible spots, and ask the store how long the fish have been in stock; fish that have settled for a week or more usually travel better.

• Quarantine new fish for 2–4 weeks if you can. This matters because some tetra imports carry mycobacteria.
• Drip acclimate over 45–60 minutes.
• Keep lights off for the first day.
• The first 48 hours are the riskiest. A sudden die-off right after purchase usually means shipping stress or a pathogen; quarantine the next batch.

For summer or winter orders, check the forecast along the delivery route and be home to receive the box so the bag does not sit in extreme heat or cold. Float and acclimate immediately.

Moving Fish Between Tanks

Match temperature and parameters first. Net gently or scoop fish out with a cup, keep lights low, and move the entire school together so no fish ends up alone.

Common Diseases

Stable, clean water prevents most problems.

• Ich: white spots like grains of salt. Raise temperature slowly to about 84–86°F (29–30°C) and use an ich medication at a reduced dose, since tetras can be sensitive.
• Fin rot: ragged, whitened fin edges. Fix water quality first; use an antibacterial treatment if it keeps progressing.
• Fungus: cottony white tufts, often on existing injuries.
• Internal parasites: fish waste away despite eating.
• Dropsy: swelling and pinecone-like raised scales. Often fatal; isolate the fish right away.
• Mycobacteriosis (fish TB): chronic wasting, bent spine and skin lesions. There is no reliable cure. Cull affected fish and disinfect nets and equipment. It can infect people, so wear gloves if you have cuts on your hands.

Head Shaking or Shimmying

Shaking the head or shimmying in place signals irritation. Common causes include gill parasites, ammonia or nitrite, a sudden parameter change, or low oxygen. Test the water and do a water change before starting any medication.

Sexing and Breeding

Sexing is very difficult. Mature females look rounder when viewed from above.

Breeding is challenging but possible:

• Use a separate 10-gallon tank with very soft, acidic water (pH about 6–6.5, GH under 4).
• Keep it at 82–84°F (28–29°C) with dim lighting.
• Add java moss or a spawning mop for the egg scatterers to use.
• Remove the adults after spawning, since they will eat the eggs.
• Eggs hatch in about 24–36 hours, and fry are free-swimming around 5–6 days later.
• Start fry on infusoria, then move to baby brine shrimp.

Similar Tetras and Alternatives

• Silvertip tetra (Hasemania nana): about 1.5–2 in, hardy, but can nip in cramped tanks. Not ideal with long-finned fish.
• Red and black phantom tetras (Hyphessobrycon sweglesi and H. megalopterus): peaceful; males spar harmlessly. They prefer cooler, softer water.
• Blue Kerri tetra (Inpaichthys kerri): small and peaceful, with blue-violet males.
• Gold tetra (Hemigrammus rodwayi): the gold sheen in wild fish is partly a skin reaction and often fades in captivity.

Common Mistakes

• Keeping fewer than 6–8 fish, which leads to hiding and washed-out color.
• Adding them to a new, uncycled or unstable tank, or rushing acclimation.
• Bright light over a bare tank.
• Letting water changes slide until nitrate climbs.
• Housing them with aggressive, much larger or nippy fish.
• Overfeeding, especially in smaller tanks.

Frequently Asked Questions

How many rummy-nose tetras should I keep?

Aim for 8–12, with 6 as the absolute minimum. Larger groups school tightly and show their best color, while small groups tend to hide and look washed out.

Why did my rummy-nose tetra's nose lose its color?

Fading is a stress signal, most often from water quality or a recent change like a move, a water change or new lighting. Test ammonia, nitrite, nitrate, pH and temperature first. The red usually returns once conditions stabilize.

Can rummy-nose tetras live with neon or cardinal tetras?

Yes. They share similar needs and may school loosely together, but each species still needs its own full group to feel secure.

Can rummy-nose tetras live with bettas or angelfish?

A calm male betta often works in a 20-gallon or larger tank. Small angelfish are fine, but large adult angels may eat rummies, so this pairing needs caution.

Are rummy-nose tetras good for beginners?

Yes, as long as the tank is mature and fully cycled. They are hardy once settled but fragile going in, so they are not a good choice for a brand-new tank.

What is the difference between true, brilliant and false rummy-nose tetras?

The brilliant rummy's red extends past the gill cover onto the body and is the most intense. The true rummy's red stays mostly on the head, and the false rummy is best separated by comparing head-color extent and the black-and-white tail stripes side by side. Care for all three is nearly the same.

Ready to Start Your School?

A long tank, stable soft-leaning water and a group of eight or more is all it takes to keep that red nose glowing. Browse rummy-noses and other schooling species in our tetra collection on FishyHub.