Saturday,15 December 2018, 9 : 10 PM

Paretroplus polyactis

P polyactis
Paretroplus polyactis
Image Credit: Fishbase

Introduction



Paretroplus polyactis is a medium sized fish in its genus. It has a standard length of 5.0" and total length of 6.0".
It is found in entire eastern coast of Madagascar.


Taxonomy

(Click for details of Cichlid taxonomy)

Paretroplus polyactis was first described by Bleeker in 1878.
The genus Paretroplus is further divided several groups called clades.
P polyactis belongs to clade consisting of fish which are deep-bodied and more or less disk-shaped members of Paretroplus.
Other members of this clade are P. dambabe, P. maculatus, P. maromandia, P. menarambo, and P. petiti.

The genus name Paretroplus comes from the Greek 'para' meaning 'on the side of'; in taxonomy it is commonly used in generic names to express similarity or relatedness.
Hence the genus name literally means 'next to Etroplus' and signifies the close relationship these two genus have.

The species name is derived from words "poly"and "actis". Poly means "many" and actis means "ray".
These refer to reddish, orange, and brown coloration of the species, which is quite striking in life.



Description

Paretroplus polyactis is a deep bodied, laterally compressed member of its clade.
It has a standard length of 5.0" and a body depth of 55 % of SL.

Head shape ranges from pointed, not blunt, and only moderately steeply sloping in lateral view, to relatively blunt and somewhat steeply sloping.
Head length is 30.9% of SL and width is 16.1 % of SL. Snout ranges from straight to moderately convex in lateral view.
Snout length is 44.3 % of Head length.
Predorsal profile is straight to moderately curved.
Caudal peduncle is short, deep, and laterally compressed.

Total vertebral count is 31 or 33, 15 vertebra on body (pre caudal) and 16-18 on tail.
Lower and upper jaws are similar (isognathous). There is a single row of thin, flat, single cusp teeth in both upper and lower jaws.
Teeth are laterally expanded, flattened at crown.
In upper jaw, tooth on either side of pre maxillary symphysial are greatly enlarged, other teeth graded in size laterally.
Lower-jaw teeth at symphysial are not enlarged, but reduced in size compared to adjacent lateral teeth, presumably to accommodate enlarged upper symphysial teeth.
Teeth in upper jaw number 5-8 on each side, and total 11–15.
Teeth in lower jaw number 4-5 on each side, and total 8-9.
Teeth in both upper and lower jaws are frequently irregularly spaced and graded in size laterally.

Like all cichlids, P. polyactis have pharyngeal teeth.
Upper and lower pharyngeal tooth plates are well developed with strong teeth.

Body is covered with large, overlapping, cycloid scales.
Flank scales on back side are thin, lack circuli(rings) , un ossified and form a flexible 'flap'.
Dorsal and Anal fin bases have well-developed ridges of scales.
Pelvic auxiliary scale are present and well developed.

Lateral-line contains 31–36 scales.

Chest scales are markedly reduced in size and embedded.
Scales along ventral midline are smallest.
There are 4-6 rows of scales on cheek. Opercle, subopercle, and interopercle are scaled.
Snout, and region near eyes does not have any scales.
Scales on caudal fin are small in size and extending posteriorly about 3/4 length of fin on dorsal and ventral lobes, and 1/3 length of fin medially.
Dorsal fin is placed vertically above pectoral fins base and has XVI–XVIII spines, 15–18 soft rays.
Soft Dorsal fin is weakly pointed.
Anal fin has VII –X spines, 13 –15 soft rays.
Soft anal fin is weakly pointed.
Caudal fin is concavely curved but not forked ( emarginate) , upper and lower lobes are broad and more-or-less rounded.
Pectoral fin is broad and rounded at the end .
Pelvic fin extends to about level of anal-fin origin.



Distribution & Habitat

Paretroplus polyactis has an extensive latitudinal range spanning nearly the entire eastern coast of Madagascar.
The known range for the species extends from somewhat north of the Masoala Peninsula, the Lokoho River at Ambatoloaka (de Rham and Nourissat, 2004: 84), southward to the Manampanihy River, located 20 km inland of Fort Dauphin.

Interestingly, although P. polyactis is primarily a coastal species throughout most of its range, frequently inhabiting estuarine and brackish habitats and generally not straying far inland, de Rham and Nourissat (2004: 85) report that the species is absent from coastal areas at the southern limit of its range near Fort Dauphin, where it is restricted to the upper reaches of the Manampanihy River.

The most southern coastal populations of P. polyactis known occur at Manombo (including rivers and streams within Manombo Special Reserve) and Vangaindrano, which are located to the south of Farafangana.
The species has also been collected about 60 km inland from the sea in the Andriambondro River (tributary of Rienana River) just to the north of Karianga.

Habitat :


Paretroplus polyactis is found in the costal region of Eastern Madagascar.
It has often been found swimming in degraded habitats and even in sea water.
It is able to tolerate brackish conditions also.

Colouration



Base colour of body is pale yellow, olive, or golden brown, and becoming pale salmon in sexually active individuals.
Body pale yellow to pale olive ventrally.
Scales on flanks have light center and dark margins giving the fish a diamond pattern look.

There are 7-9 black vertical bars present on flanks.
Populations from Mananjary northward possess eight or nine lateral bars, whereas those along the southeastern coast and inland from about Karianga and Farafangana (22uS) southward have seven lateral bars.

Head region is generally darker than flanks, but with same pale yellow, olive, or golden brown coloration.
Opercle and cheek frequently have some iridescent bright golden patches.
Upper lip, inter orbital region, lacrimal, and snout are grayish brown to uniform dark brown.
Iris of eye are bright red, which gives species its Malagasy name masovoatoaka, which translates as ‘‘eyes bloodshot from drinking (rum)’’.
Lower lip, gular region, anterior chest, belly, interopercle, and ventral cheek are white, pale yellow, or light olive.
Unpaired fins are dark gray, charcoal, or black, with dark red margins.
Pectoral fins range from hyaline to translucent brown or black.
Pelvic fins dark gray to black, with light gray to whitish leading edge.
Juveniles to about 60 mm SL with well-differentiated lateral bars that extend vertically over entire flank.
Although still prominent, lateral bars become wider and less well differentiated in adults.



Conservation Status & Threats



IUCN Red list shows status of Paretroplus polyactis as "Vulnerable".
Paretroplus polyactis previously was listed as Lower Risk, least concern.
Improved information since then has resulted in the species being up listed to Vulnerable.
Although it is distributed throughout many rivers of the eastern slopes of Madagascar,the estimated extent of occurrence is less than 20,000 km² and the population is fragmented.
There is a continued decline in extent of occurrence, area of occupancy and the number of mature individuals due to habitat loss from deforestation in the water catchments, and overfishing.

Major Threats:
Habitat destruction, overfishing, and competition from a number of exotic species, primarily tilapiine cichlids and the Asian snakehead are major threats faced all madagascar Cichlids.



Tank Size and setup:


It is a medium to large size fish.
Given the fact that these cichlids love to live in groups a tank should not be less than 500 liters.
Water Parameters:
These fish live in rivers near costal area, specimens have been seen swimming even in sea. Hence the fish is able to live in brackish conditions.

Feeding



It is carnivore and should be given corresponding diet.Frozen shrimp, mussels, live snails can be give.

Breeding



There are no sexually dimorphic features apparent, but although unpaired fins of males are slightly more elongate and pointed distally than females of comparative standard length. Not much information is available on breeding habits of this fish.



Species Snapshot

Species Card


Particulars Details
Scientific Name Paretroplus polyactis
Common Name Masovoatoaka
Genus Paretroplus
Subfamily Etroplinae
Geographical Origin Africa: Madagascar.
Diet Carnivore
Gender Differences Mono morphic
Breeding Substrate Spawner
Temperament Mildly aggressive
Con Specific Temperament Mildly aggressive
Water hardness ph range ; 6.5 to 8
Difficulty Level in Aquariums 4


Morphometric Data


Particulars Details
Total Length(inches) 6.50
Standard Length(inches) 5.00

Measurements as % of Total Length


Particulars Details
Body Depth 54.90 %
Head length 30.90 %
Pre Dorsal length  %
Pre Pectoral length  %
Pre Anal length  %
Pre Pelvic length  %
Caudal Peduncle Depth 15.90 %
Caudal Peduncle Length 8.20 %
Fork length  %
Length of Last Dorsal Fin Spine  %
Pectoral Fin Length 22.30 %
Pelvic Fin Length 21.20 %

Measurements as % of Head Length


Particulars Details
Head Width 16.10 %
Snout length 44.30 %
Eye diameter 28.70 %
Pre Orbital Length  %
Inter Orbital Width 31.40 %
Pre Orbital Depth  %



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