Encyclopaedia
True Rummy-Nose Tetra
Hemigrammus rhodostomus
The *Hemigrammus rhodostomus* is the 'True' Rummy-Nose Tetra, often confused in the aquarium trade with the almost identical and more widespread *H. bleheri* (the common Rummy-nose) and the *Petitella georgiae* (False Rummy-nose). It is distinguished from the Bleheri by the red coloration of the snout which is strictly confined to the head and DOES NOT extend beyond the gills, and by the presence of a faint dark line running along the caudal peduncle until it merges with the spectacular black and white zebra stripes of the caudal fin. Slightly larger than the Bleheri (up to 5-6 cm / 2.5 inches) and with a more silvery body, it is a tireless pelagic swimmer and one of the most cohesive and spectacular schooling fish that can be hosted in large South American aquariums.
- Family
- Characidae
- Origin
- Sud America (Bacino inferiore del Rio delle Amazzoni e fiume Orinoco in Venezuela e Brasile)
- Origin
- Amazon, Orinoco, and Guianas
- Tank use
- Used in 0 tanks
Share
24 °C - 28 °C
5.5 - 7
Freshwater
Middle
5 cm
Description
Geographic Origin and Biotope: Lower Amazon River Basin in Brazil. Compared to the Bleheri ("false" Rummy), the Rhodostomus inhabits areas further downstream, in clear but peaty rivers (Clear/Black water mix).
Taxonomy and Morphology: True Rummy-Nose Tetra (Hemigrammus rhodostomus). Slender, with hypnotic swimming. The main characteristic to distinguish it from the bleheri is that the red coloring NEVER extends beyond the gills.
Social Behavior: Like their cousins, they are slaves to the school (extreme Shoaling Fish). A single H. rhodostomus or in a microscopic group (3 fish) stops swimming in open waters to hide behind filters until it dies of starvation.
Coloration and Sexual Dimorphism: Tip of the snout stained with cherry, with a semi-transparent silver body and a conspicuously zebra-striped tail (black-white). In females the abdomen is increasingly "square" towards the bottom due to the ovarian sacs.
Care and observations
Aquarium Setup: Classic rectangular aquarium (minimum 80-100 cm / 32-40 inches). They obligatorily need a dense back side full of plants (Cabomba, Myriophyllum) to give them the security of diving for cover, but the front 70% of the tank must be empty for frantic swimming.
Diet and Feeding: Gluttonous for springtails and insects, in captivity they accept fine crushed dry granules and freeze-dried food (Daphnia, Tubifex). Quality feed and liquid vitamins enhance facial red pigmentation.
Water Quality: The absolute biological indicator: the red snout fades at the first sign of nitrites or ammonia spikes. The water must be mature (cycled for months) and preferably softened with oak extracts.
Compatibility and Tankmates: The "Dither fish" par excellence. It is paired with large peaceful cichlids (Apistogramma, Geophagus, Satanoperca, Angelfish) since their quiet but tireless swimming signals to the cichlid that "there are no predators lurking" in the tank.
Aquarium Reproduction: Scatterer of photosensitive eggs. They require a very mature sponge filter (newborns eat infusoria), and a total absence of light. Upon hatching, larvae cannot withstand strong lighting for the first 2 weeks.
Risks and Diseases: Decimation from water stress. Water changes made with significant thermal shock (even just 2-3°C / 4-5°F) cause swimming paralysis or terrifying Ich infestations.
Fish profile
- Temperament
- Puro pacifico, perennemente in movimento sincrono. Non è mai aggressivo verso altre specie né all'interno del proprio branco.
- Diet
- Onnivoro. Accetta avidamente cibo secco di alta qualità, ma i colori del muso e i contrasti della coda esplodono solo se integrati quotidianamente con artemia salina viva o congelata, dafnie e micro-chironomus. Le loro bocche sono piccole, necessitano di granulati fini affondanti (1 mm).
- Tank level
- Middle
- Minimum group
- 10
- Adult size
- 5 cm
- Minimum tank
- 120 L
- GH
- 1 dGH - 10 dGH
- KH
- n/a
- TDS
- n/a
- Conductivity
- n/a
- Sex ratio
- Branco stretto obbligatorio (più sono, migliore è l'effetto visivo del loro nuoto, minimo 10). Le femmine adulte sono molto più tozze e gravide (rotonde) rispetto ai maschi spiccatamente affusolati a forma di siluro.
- Feeding frequency
- 1-2 volte al giorno in dosi distribuite per tutta la lunghezza della vasca, per evitare risse alimentari nel branco in movimento.
- Bioload
- Medio-Basso
- Flow
- Corrente da Moderata a Forte. Sono eccellenti nuotatori e amano contrastare il flusso in formazione.
- Reproduction
- Dispersori di uova 'in campo aperto'. Molto complessa da indurre in cattività senza una preparazione chimica certosina. Richiedono acqua estremamente tenera e acida (Torbata, pH sotto 6.0) e luce quasi inesistente, poiché le uova sono molto sensibili all'attacco fungino in acque dure.
- Compatibility
- I 'Dither fish' perfetti per eccellenza per grandi acquari amazzonici. Data la loro taglia adulta (6 cm), sono gli unici Caracidi sufficientemente grandi (se inseriti adulti) e veloci da poter convivere tranquillamente in enormi vasche dedicate agli Scalari (Pterophyllum altum) e perfetti con pesci di fondo pacifici come Corydoras e Geophagus.
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.