No established common name
Megalamphodus khardinae
Megalamphodus khardinae features a slender body with a shimmering silver hue and distinct orange-red markings along its dorsal and anal fins.
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About the No established common name
Tiny rosy-tetra relative from the lower Purus blackwaters in Brazil with a neat triangular shoulder spot and red-tipped dorsal and adipose fins. Keep a good-sized group and they will glow over leaf litter and show off those subtle oranges. They appreciate soft, acidic water like their slow, tea-colored home creeks.
Quick Facts
Size
3.9 cm SL (1.5 inches)
Temperament
Peaceful
Difficulty
Intermediate
Min Tank Size
20 gallons
Lifespan
3-5 years
Origin
South America
Diet
Omnivore - micro-pellets, quality flakes, frozen/live daphnia and brine shrimp
Water Parameters
24-28°C
5-6.5
0-6 dGH
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This species needs 24-28°C in a 20 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Give them a long tank and a crowd: think a 20-long or bigger with 12+ fish, dark sand, wood, leaf litter, and floating plants to keep light soft.
- They want true soft, acidic water: RO or rainwater mix, pH 5.0-6.5, GH 0-5, KH 0-2, TDS roughly 40-120 ppm, 75-80 F, gentle flow and good oxygen.
- Acclimate slow (drip 60-90 min) and keep changes small but steady; match temp and TDS on water changes and keep nitrates under ~15 ppm.
- Feed tiny foods often: baby brine, daphnia, cyclops, mosquito larvae, plus micro-pellets or crushed flakes; 2-3 small feedings beats one big dump.
- Tankmates should be calm and soft-water friendly: pencilfish, hatchetfish, small Corydoras, maybe dwarf Apistos if not breeding; skip barbs, danios, large tetras, and bettas.
- They color up and act brave when the group is big and the tank is dim; if they hide, add more of their own and more cover.
- Breeding is classic egg scatter: very soft, dark, pH ~5.5 at ~78 F, fine plants or a mesh, remove adults right after; eggs are light sensitive, fry start on infusoria then baby brine.
- Watch for hard-water burnout and ich after chilly water changes; wild-caught fish often have worms, so a levamisole or flubendazole round early can save headaches.
Compatibility
Good Tankmates
- Small, chill schooling fish like ember tetras, glowlight tetras, and harlequin rasboras
- Peaceful bottom crew: Corydoras (including pygmy species) that ignore midwater fish
- Gentle algae helpers like Otocinclus that mind their own business
- Surface hangers with calm vibes: pencilfish and hatchetfish
- Tiny, mellow gouramis like honey or sparkling gourami in a planted setup
- Shrimp and snails for cleanup - adults do fine, but expect the odd baby shrimp to go missing
Avoid
- Anything nippy or rowdy: serpae tetras, tiger barbs, Colombian blue tetras
- Big or predatory cichlids that see small tetras as snacks - angels, convicts, oscars
- Fin bullies and fast food hogs like giant danios and larger rainbowfish
- Very slow, long-finned showpieces that get stressed by active schooling fish - fancy guppies, veil bettas
Where they come from
Megalamphodus khardinae is one of those lesser-seen South American tetras from quiet forest creeks. Think tea-colored water, leaf litter, and overhanging branches. They are right at home in dim, soft, slightly acidic conditions with lots of cover.
Tank setup
Give them room to school and keep things calm. A 20-gallon long is a nice starting point for a proper group. They look best over a dark substrate with botanicals and wood. Keep the flow gentle and the lighting subdued.
- Temperature: 75-81 F (24-27 C)
- pH: 5.5-6.8
- GH: 1-6 dGH
- KH: 0-3 dKH
- TDS: roughly 50-150 ppm
I run a big sponge filter or a canister with a spray bar aimed at the glass for a soft current. Floating plants like Salvinia or water lettuce help with shade. A few catappa leaves or alder cones add tannins and make them feel secure.
Use RO or very soft tap, then remineralize lightly so KH lands around 1-2. That keeps the pH stable without making the water hard.
They appreciate cover. Pile in fine-leaved stuff (Myriophyllum, Cabomba) or even spawning mops. Keep a tight lid; they are quick and can jump if startled.
Do smaller, consistent water changes (20-30% weekly) and match temperature and TDS. Sudden swings bother softwater tetras more than a tiny bit of nitrate ever will.
Feeding
Small mouths, big appetites. They do great on a mix of fine foods. I rotate to keep them colored up and eager.
- Quality micro-pellets or crushed flake as the staple
- Live or frozen baby brine shrimp, daphnia, cyclops for conditioning
- Occasional microworms or vinegar eels for very small mouths
Feed lightly twice a day. If you see bellies bulging regularly or food hanging in the flow, cut back. Clean water keeps their fins crisp and colors rich.
Behavior and tankmates
Peaceful, school-oriented, and a little shy under bright light. In a group of 10+ they relax, males display, and you get that tight midwater shimmer. Males tend to be slimmer with a bit more color and a showier dorsal.
- Great with other small, calm characins, pencilfish, and hatchetfish
- Bottom buddies: small Corydoras and timid dwarf plecos
- Dwarf cichlids can work if the cichlids are not breeding
- Skip boisterous or nippy fish and anything that likes long fins
Keep them in a proper group. Too few and they get skittish and may pick at tankmates. A big school spreads out any pushiness and shows their best behavior.
Breeding
They are classic softwater egg scatterers. It is doable at home if you set them up for success and keep the light low.
- Condition a small group with live foods for a week
- Breeding tank: bare bottom, dim, with a mesh or marbles on the bottom and clumps of fine plants or mops
- Water: very soft and acidic (pH 5.5-6.2, GH 1-3), around 77-79 F (25-26 C)
- Introduce a pair or 1-2 males with 2-3 females in the evening; they usually spawn at first light
- Remove adults right after eggs appear; they will eat them
- Keep the tank very dim. Eggs are light-sensitive and can fungus under bright light
Eggs hatch in about a day, and fry go free-swimming 3-5 days later. Start them on infusoria or paramecium, then move to microworms and newly hatched brine shrimp once they can take it.
Alder cones or a little catappa leaf in the breeding tank helps with fungus control without resorting to dyes. Gentle aeration only; no strong flow.
Common problems to watch for
- pH swings in ultra-low KH: If your KH is near zero, even a modest water change can shift pH. Remineralize lightly and pre-match your new water.
- Stress after shipping: Quarantine, keep lights low for the first few days, and feed lightly. They color back up once settled.
- Ich and fin issues: Sudden chills or rough tankmates bring this on. Treat promptly and raise temperature gradually if needed. Go gentle with meds; many tetras are sensitive.
- Washed-out color under bright light: Add floating plants and darker decor. They show more in shade.
- Jumping: Startle jumps happen. Tight lids save fish.
Avoid hard, alkaline water long term. They can survive it, but you will see chronic stress, thin bodies, and poor color. Soft, slightly acidic water makes all the difference with this species.
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