Edit Nannostomus marginatus

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Name

Scientific name

Nannostomus marginatus

Described by

Authority Eigenmann, Year 1909

Family

Lebiasinidae

Common names

Dwarf Pencilfish

Photograph credits

All 10 credited

Summary

The dwarf pencilfish, Nannostomus marginatus, is a lebiasinid of Guyana, Suriname and the middle-to-lower Amazon in Peru, Colombia and Braz…

Size and aquarium

Maximum size

25mm, standard length

Aquarium size

Minimum length 45 cm, Minimum depth 30 cm, Water movement Low: still or sluggish water

Water

Water conditions

Temperature 22–28°C, pH 4–7

Hardness

1–10dGH

Conductivity

Not recorded

Behaviour

Temperament

Peaceful

Community suitability

Not for a community

Where it lives

Countries, regions, rivers and lakes

Brazil, Colombia, Guyana, Peru, Suriname, Amazon, Ampiyacu, Branco, Caquetá, Corantijn, Courantyne, Demerara, Essequibo, Inírida, Japurá, Jurua, Napo, Negro, Nickerie, Putumayo, Rupununi, Takutu, Trombetas, Ucayali, Yavarí

Writing

Etymology

Nannostomus: from the Latin nannus, meaning 'small', and Greek stoma, meaning 'mouth', in reference to the small mouthparts of member species. marginatus: from…

Distribution

Type locality is 'Maduni Creek, Guyana', and this species is widely-distributed throughout Guyana and Suriname, plus the middle-to-lower Amazon basin east of t…

Habitat

Inhabits sluggish tributaries, small rivers and swampy areas, particularly in areas with dense growth of aquatic vegetation or submerged woody structures and l…

Inhabits sluggish tributaries, small rivers and swampy areas, particularly in areas with dense growth of aquatic vegetation or submerged woody structures and leaf litter.

It's often found in areas of flooded forest and floodplain lakes in blackwater regions.

Typical habitats contain shallow, near still water with very little detectable hardness, low conductivity, and a pH of 4.0-6.0, with other fishes comprising small characids, other lebiasinids, and dwarf cichlids of the genus Apistogramma.

La Arenosa is a small stream in Amazonas department, southern Colombia flowing down from terra firme forest into a floodplain of the Amazon mainstream.

It varies from 2-5 m in width and up to 2 m in depth and contains slowly-moving, clear blackwater the majority of the time, temporarily increasing in depth and flow rate after storms.

PH ranges from 5.51-6.01, conductivity 18-38 µS/cm, dissolved oxygen 70%, and an average water temperature of 25 °C77 °F.

N. marginatus was found to be a permanent resident of the stream in a study conducted over a period of one year, with symaptric species includingthe congener N. trifasciatus plus Axelrodia stigmatias, Hemigrammus analis, H. bellottii, H. ocellifer, H. schmardae, H. copelandi, Moenkhausia comma, M. sanctafilomenae, Tyttocharax cochui, Tetragonopterus argenteus, Characidium zebra, Crenuchus spilurus, Hoplias malabaricus, Carnegiella strigata, Copella nattereri, Corydoras semiaquilus, Megalechis thoracata, Limatulichthys griseus, Farlowella amazona, Eigenmannia virescens, Aequidens diadema, Apistogramma bitaeniata, Satanoperca sp., Cichla monoculus, Crenicichla saxatilis, and Monocirrhus polyacanthus.

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Where does this come from?

My own experienceFor example, I've kept twelve in a planted 60 cm tank since March 2024.A website I sawFor example, an IUCN Red List assessment, a museum catalogue or a FishBase page.A paperFor example, Marshall et al. (2011), Water temperature differences in interfluvial palm swamp habitats of Paracheirodon axelrodi and P. simulans.A book, or something not onlineFor example, Tappin (2010), Rainbowfishes: their care and keeping in captivity.Something already on the pageFor example, the Behaviour and compatibility section already says this.

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Year

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Aquarium size

Base dimensions of at least 45 ∗ 30 cm or equivalent are necessary.

Maintenance

Should ideally be kept in a heavily-planted set-up, preferably with a dark substrate. The broken lines of sight that exist in such a display allow it to displa…

Water conditions

Not written yet

Diet

A micropredator feeding on tiny invertebrates and other zooplankton in nature. In the aquarium it will accept dried foods of a suitable size but should also be…

Behaviour and compatibility

Very peaceful but does not make an ideal community fish due to its small size and rather timid nature. It's best kept with similarly-sized, peaceful characids …

Sexual dimorphism

Adult males are noticeably less stocky than females, and in one form from the rio Negro males possess a modified anal-fin with the third to sixth rays being th…

Reproduction

Has been achieved in aquaria, albeit rarely, and in a densely-planted, mature aquarium it's possible that small numbers of fry may start to appear without inte…

Notes

This species is enduringly popular in the aquarium hobby and is one of a group of congeners, also including N. mortenthaleri (originally described as a subspec…

References

7 on this profile

Name

Scientific name

Described by

Family

Common names

Photograph credits

Summary

Size and aquarium

Maximum size

Aquarium size

Water

Water conditions

Hardness

Conductivity

Behaviour

Temperament

Social needs

Community suitability

Where it lives

Countries, regions, rivers and lakes

Writing

Etymology

Distribution

Habitat

Aquarium size

Maintenance

Water conditions

Diet

Behaviour and compatibility

Sexual dimorphism

Reproduction

Notes

References

References