Edit Nannostomus marilynae

You can suggest changes to this profile. A moderator will review each change.

Name

Scientific name

Nannostomus marilynae

Described by

Authority Weitzman & Cobb, Year 1975

Family

Lebiasinidae

Common names

Greenstripe Pencilfish

Photograph credits

All 3 credited

Summary

The greenstripe pencilfish, Nannostomus marilynae, occurs in the rio Negro in Brazil and the Río Vichada in the upper Orinoco basin, Colomb…

Size and aquarium

Maximum size

35mm, standard length

Aquarium size

Minimum length 60 cm, Minimum depth 30 cm, Water movement Low: still or sluggish water

Water

Water conditions

Temperature 21–28°C, pH 4–6.5

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, Negro, Orinoco, Vichada

Writing

Etymology

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

Distribution

The type series was collected from 'rock pools below rapids, São Gabriel,' which probably refers to the city of São Gabriel da Cachoeira which lies on the rio …

Habitat

Likely to inhabit sluggish tributaries, small rivers and swampy areas, particularly in areas with dense growth of aquatic vegetation or submerged woody structu…

Aquarium size

Base dimensions of at least 60 ∗ 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

Relatively peaceful and will not compete well with very boisterous or much larger tankmates. In a community it's best kept with similarly-sized, peaceful chara…

Sexual dimorphism

Adult males are usually slimmer and more intensely-patterned than females. Males also possess a slightly modified anal-fin with the anterior 5-6 branched rays …

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 also known as 'Marilyn's pencilfish'. It's rarely traded in numbers and more often seen as bycatch among shipments of other species, particular…

This species is also known as 'Marilyn's pencilfish'.

It's rarely traded in numbers and more often seen as bycatch among shipments of other species, particularly Paracheirodon axelrodi.

It can be identified by the following combination of characters: three dark lateral stripes (sometimes referred to as primary, secondary, and tertiary); nocturnal oblique bars relatively narrow, with the anterior bar reaching, but not extending past, the anterior base of the dorsal-fin, and posterior bar not extending beyond posterior base of the anal-fin; adipose-fin always present; 24-27 scales in the lateral series; anal-fin in males not elongate and only slightly modified with the anterior 5-6 branched rays slightly elongate and thickened; lower caudal-fin lobe somewhat larger than upper lobe.

In terms of appearance it's most similar to N. minimus but lacks the highly-modified anal-fin seen in male individuals of that species, and also exhibits some similarities with N. trifasciatus but differs in both diurnal and nocturnal colour pattern.

Don't worry if your fish look different when you switch on the aquarium lights after dark or in the morning as like most Nannostomus species it assumes a cryptic, vertically-barred colour pattern at night.

This diurnal rhythm has been show to occur in blind specimens, suggesting it's an automatic response that the fish cannot control.

The family Lebiasinidae is included in the order Characiformes and sometimes split into the nominal subfamilies Lebiasininae and Pyrrhulininae, though there has not been a major review of the grouping in recent times.

All lebiasinid genera possess a relatively long, elongate body shape with 17-33 scales in the lateral series and laterosensory canal system absent or reduced to 7 scales or less.

Some species have an adipose fin while others do not, and the anal-fin has a relatively short base of 13 scales or less.

In the majority of members males have an enlarged or otherwise well-developed anal-fin used in courtship and spawning.

The frontal/parietal fontanelle is always absent, the cheek well-covered by the orbital and opercular bones, the supraoccipital crest is absent, and the scales of the dorsal body begin over the parietal bones.

Characiformes is among the most diverse orders of freshwater fishes currently including close to 2000 valid species distributed among 19 families.

This tremendous taxonomical and morphological diversity has historically impaired the ability of researchers to resolve their genetic relationships with many genera remaining incertae sedis.

A further limiting factor has been that in many cases exhaustive study of these on an individual basis is the only way to resolve such problems.

Modern molecular phylogenetic techniques have allowed some headway, though, and a research paper by Calcagnotto et al. published in 2005 revealed some interesting hypotheses.

Their results suggest that Lebiasinidae forms a trans-atlantic, monophyletic clade alongside the families Ctenoluciidae and Hepsetidae, this clade further forming a sister group to Alestidae.

Others such as Oliveira et al. (2011) have concluded that the family Erythrinidae is also closely-related to this grouping with Hepsetidae and Alestidae more distant.

Editing needs JavaScript. This is the text as it was last saved.

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.

Web address

Paste the address of the page that says this. What counts as a source

DOI

Paste a DOI and we will look up the rest of the reference. A DOI looks like 10.11646/zootaxa.4694.4.1, and most papers print it on the first page.

Title

Enter the title of the paper, book or page. If you leave it empty, we will use the website's address.

Authors

Separate authors with semicolons, e.g. Tan, H.H.; Ng, P.K.L.

Year

Journal or publisher

Pages

Enter the page that says this, e.g. 218 or 218–221.

Anything worth adding

Describe what you saw, or which part of the source says this.

References

3 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