Black Skirt Tetra
Gymnocorymbus ternetzi
Characidae
FishDifficulty: ●●○○○Data: well-established
About
The black skirt tetra is a hardy, deep-bodied characin from the Paraguay and Guaporé river basins of central South America, named for the smoky black rear half and flowing anal fin that fade to translucent grey with age. Lively and undemanding, it is an excellent community fish but carries a reputation as a fin-nipper, particularly when kept in cramped quarters or thin groups. A generous shoal in a spacious, planted tank with open swimming room keeps its energy focused inward and greatly reduces nipping.
Care
Keep in an active shoal of 8 or more (larger is better for curbing nipping) in a planted tank of at least 75 L with plenty of open swimming space. Occasional fin-nipper: avoid slow, long-finned tankmates such as bettas, angelfish and fancy guppies.
Diet
Adaptable omnivore; feed varied dry foods alongside regular frozen or live daphnia, bloodworm and mosquito larvae to maintain condition and activity.
Tankmate compatibility
Gets along with (55)
Agassiz's CoryBanjo CatfishBlack Neon TetraBlack Phantom TetraBlack Ruby BarbBlackline RasboraBloodfin TetraBlue Tiger ShrimpBolivian RamBorneo SuckerBristlenose PlecoBronze CorydorasCelestial Pearl DanioCherry BarbClown KillifishCochu's Blue TetraDenison BarbDoctor FishEmerald CoryEmperor TetraFlame TetraGlass CatfishGlowlight DanioGold BarbGolden Dwarf CichlidGolden PencilfishHarlequin RasboraHead-and-Tail-Light TetraHoney GouramiJulii CoryKeyhole CichlidLambchop RasboraLemon TetraLeopard DanioLittle CorydorasOtocinclusPanda CorydorasPearl DanioPenguin TetraPictus CatfishPurple Emperor TetraPygmy CorydorasRed Whiptail CatfishReticulated Hillstream LoachSalt and Pepper CoryScarlet BadisScissortail RasboraSiamese Algae EaterSkunk CoryStriped KribensisThai Micro CrabUmbrella Dwarf CichlidUpside-down CatfishX-ray TetraZebra Danio
Possible with care (121)
African Butterfly CichlidAfrican ButterflyfishAgassiz's Dwarf CichlidAmano ShrimpAssassin SnailBamboo ShrimpBetta (Siamese Fighting Fish)Bladder SnailBleeding Heart TetraBlood Parrot CichlidBlue AcaraBlue Dolphin CichlidBlue Velvet ShrimpBoesemani RainbowfishBrichard's TeleogrammaBuenos Aires TetraBuffalohead CichlidBumblebee GobyButterfly Hillstream LoachCardinal TetraCelebes RainbowfishCheckerboard CichlidCheckered BarbCherry ShrimpChili RasboraChinese Algae EaterChocolate CichlidChocolate GouramiClown PlecoCockatoo Dwarf CichlidColombian Ramshorn SnailCongo Dwarf CichlidCongo TetraConvict CichlidCrystal Red ShrimpDiamond TetraDojo (Weather) LoachDwarf Chain LoachDwarf Flag CichlidDwarf GouramiDwarf Neon RainbowfishDwarf Orange CrayfishDwarf Pea PufferDwarf RasboraElephantnose FishEllioti CichlidEmber TetraEndler's LivebearerFeatherfin SqueakerFestivum (Flag Cichlid)Figure-8 PufferFiremouth CichlidForktail RainbowfishFreshwater ClamGerman Blue RamGhost ShrimpGlowlight TetraGolden TetraGolden Wonder KillifishGreen Neon TetraGuppyJapanese Trapdoor SnailJewel CichlidKissing GouramiKribensisKuhli LoachLeast KillifishMacmasteri Dwarf CichlidMalaysian Trumpet SnailMarble HatchetfishMedaka RicefishMoonlight GouramiMystery SnailNeon TetraNerite SnailOdessa BarbParadise FishParaguay EartheaterPeaceful BettaPearl GouramiPeppered CorydorasPlatyPolka Dot LoachPort CichlidRabbit SnailRainbow CichlidRainbow SharkRamshorn SnailRed RainbowfishRed-Tail SharkRedhead CichlidRosy BarbRosy TetraRubber Lip PlecoRummynose TetraSailfin MollySerpae TetraSeverumSilver Tip TetraSparkling GouramiSpotted HoploSterbai CorydorasStrawberry RasboraSulawesi Cardinal ShrimpSunshine PeacockSveni EartheaterSwordtailT-Bar CichlidThick-lipped GouramiThreadfin AcaraThreadfin RainbowfishThree-spot GouramiTiger BarbTurquoise RainbowfishUaru (Triangle Cichlid)Vampire ShrimpVenezuelan CoryWhite Cloud Mountain MinnowWrestling HalfbeakYoyo LoachZebra Pleco
Avoid (95)
Acei CichlidAdonis PlecoAltum AngelfishAngelfishAuratus CichlidBala SharkBlack Moor GoldfishBorleyi (Redfin Hap)Brevis Shell DwellerBrichardi (Fairy Cichlid)Bumblebee CichlidCalvus CichlidClown LoachCobalt Blue ZebraComet GoldfishCommon GoldfishCommon PlecoCompressiceps CichlidCuckoo CatfishCylindricus CichlidCyprichromisDemasoni CichlidDemon EartheaterDiscusDogtooth CichlidDuboisi TropheusDwarf Petricola CatfishElectric Blue AhliElectric Yellow LabElongate MbunaEndlicheri BichirEven-spotted SynodontisFantail GoldfishFive-bar CichlidFrontosaGoby CichlidGolden JulieGreen DiscusGreen Spotted PufferfishGreen TerrorHeckel DiscusHongi CichlidIridescent SharkJack DempseyJaguar CichlidJohanni CichlidKenyi CichlidKoiLemon CichlidLivingstoniMaingano CichlidMalawi EyebiterMalawi HawkMarlieri CichlidMasked JulieMollyMultifasciatus Shell DwellerOcellatus Shell DwellerOranda GoldfishOrnate BichirOscarPeacock BassPeacock CichlidPike CichlidPowder Blue CichlidRanchu GoldfishRed DevilRed EmpressRed TerrorRed Zebra CichlidRegan's JulieReticulated Flying FoxRostratusRosy Red MinnowRoyal PlecoRusty CichlidRyukin GoldfishSailfin PlecoSalvini CichlidSand-sifting XenotilapiaSaulosi CichlidShubunkin GoldfishSilver ArowanaSilver MoonySimilis Shell DwellerStar SapphireStriped Raphael CatfishTaiwan Reef CichlidTelescope GoldfishTexas CichlidThreadfin PetrochromisTropheusVenustus (Giraffe Cichlid)Wolf CichlidZebra Mbuna
Computed by the AquaSage engine for a spacious reference tank — always check the full verdict for your exact setup in the calculator.
Telling males from females
What works for this species, most reliable first.
- Belly depthA hint only · only on well-fed adults, and only as a comparison
For most tetras, barbs and rasboras this is all there is: a conditioned female is deeper through the belly than a male of the same length.
Also in these lists
Frequently asked questions
- What tank size does a Black Skirt Tetra need?
- A Black Skirt Tetra needs an aquarium of at least 75 litres (19.8 US gallons) with a footprint at least 75 cm (29.5 in) long — for this species, swimming length matters as much as raw volume.
- What water parameters does a Black Skirt Tetra need?
- Black Skirt Tetra does best at 20–27 °C (68–80.6 °F), pH 6–7.5 and a general hardness of 5–20 °dGH.
- What group size does a Black Skirt Tetra need?
- Black Skirt Tetra is a social species — keep a group of at least 8 so natural behaviour emerges and stress stays low.
- Is the Black Skirt Tetra suitable for beginners?
- Yes — Black Skirt Tetra is one of the easier species to keep and forgives typical first-tank mistakes, as long as the aquarium is cycled and maintained.
Sources
Water & tank
Temperature20–27°C
Optimal temp.22–25°C
pH6–7.5
Hardness (GH)5–20°d
Carbonate (KH)1–10°d
Adult size6 cm
Min. volume≥ 75 L
Min. tank length≥ 75 cm
Group size≥ 8
Swimming zoneMid
TemperamentSemi-aggressive
Water typeFreshwater
FlowLow
Lifespan~5 yrs
Try in the calculator