Sunday,26 September 2021, 7 : 34 AM

Andinoacara rivulatus

Andinoacara rivulatus
Image Credit: Alf Stalsberg


Andinoacara rivulatus is one of the larger size member of its genus.
It has a TL(Total length) of 8 ".
It is found in drainage of rivers Esmeraldas, Guayas, Clementina,Túmbes in Ecuador, Peru, South America.


(Click for details of Cichlid taxonomy)

Andinoacara rivulatus was first described by Günther in 1859 as Aequidens rivulatus.
There is some confusion on type locality of this description, as well as its correct identity.
There are three very similar looking fish, which have now been classified as three different species only in 2009 and 2012 as A. blombergi, and A. stalsbergi.

The genus name Andinoacara is formed by two words "Andino" and "Acara".
Andino refers to Andes Mountain Chain in South America, these cichlids are found on the slopes of Andes mountains and in the valley formed by three arms of Northern Andes.
The term "Acara" has been used historically for Cichlids.
So the term Andinoacara literally means "Cichlids from Mountain Andes".
The latin name of this species "rivulatus", means lives in river, which is the preferred habitat of this fish.


Shape :- Body shape is moderately deep and laterally compressed.
The body is deeper than A. blombergi, body depth is 51% of SL.
Predorsal outline is straight ascending, It is steeper than pre pelvic outline, and curves slightly behind eyes or close to dorsal fin base.
Large males show a steep straight ascending frontal outline which makes a steep curve just before dorsal fin origin and proceeds straight thereafter.
Some males may have distinct nuchal hump.
Dorsal-fin base is slightly curved or straight except for stronger curvature immediately before caudal peduncle. Pre pelvic contour is sloping, straight or slightly curved.

Head, Snout, Eyes :-

  • Head is relatively short, and comparatively larger than A blombergi, having a width of 22% of SL and length of approx 37 % of SL.
  • Snout is somewhat produced, 11 % of SL.
  • Eyes are placed on upper half middle of head.
    Eyes are spaced wider, space between two eyes is 15 % of SL .
  • Inter orbital space is flat or slightly convex, slightly narrower than mouth width.

Mouth :-

  • Mouth is terminal.
  • Upper jaw slightly projects before lower jaw, and extends to the back of head and is placed vertically halfway between nostril and orbit.
  • Lips are moderately thick, both upper and lower lip folds are interrupted in middle.

Gill rakers :-

Gill rakers are evenly spaced, short and stubby and found on the outside margin of the arch.
There are 1-3 rakers in the upper arm of the arch, one in the angle (joint) of the arch and 7-10 rakers on the lower arm.
The first two arches are free and the others are held up in the middle.


Teeth in both jaws are caniniform, there is an outer row of strong teeth, progressively larger toward symphysis, and a narrow band and much smaller teeth anteriorly.
Outer row teeth may be worn off in large specimens.
Outer row of teeth are erect or slightly retrorse, fixed or slightly movable.
The teeth are unicuspid with slightly recurved tip, larger than inner teeth, very slightly increasing in size from posterior to symphysial, tips narrow, rounded, some teeth with abraded tip.
Inner teeth are present in narrow band of anteriorly 2-6 rows in upper jaw,3-4 rows in lower jaw.
Inner teeth are similar in shape to outer teeth but much shorter, slightly retrorse, depressible, few with abraded tip.
Teeth in outer hemiseries in upper jaw 12-24, in lower jaw 12-21.
Like all cichlids Oscar have teeth in not only their jaws but also a set of pharyngeal teeth.
Lower pharyngeal jaw is, somewhat slender, length 86 % of width, toothed area length 64 % of width.

Scales :-

There are 23- 24 scales in E1 row, this sets it apart from A.blombergi.
Scales on cheek, gill cover, anterior nape, chest and pre pelvic area are cycloid, remaining scales are slightly ctenoid.
Cheek area has 3-4 scales rows.
Predorsal scales have a definite midline row with posterior overlapping scale pairs, scales along midline are smaller than adjacent scales and smaller as we move towards the tail.
Their number is between 8-11.
Pre pelvic scales are embedded in skin, smallest about half size of flank scales.
As with all cichlids, lateral line is interrupted.
Upper lateral line has 15- 19 scales, it is separated from dorsal fin by 4 to 4.5 scales in front and 1.5 scales in posterior.
Lower lateral line has 8-10 scales, it continues by 1-2 tubed scales basally on caudal fin.
There are 16 scales in circumpeduncular row.
There are no scales in fins, except caudal fin which has small cycloid scales basally to almost middle.

Dorsal Fin :-
  • Dorsal-fin spines increase in length to till 6th spine , from which sub equal in length, last two spines are slightly longer.
  • Dorsal-fin spine count is between 14 to 16.
  • Dorsal soft rays are branched and their number is between 10- 11.

Anal Fin :-
  • First anal spine is inserted two spines before last dorsal fin spine (antepenultimate).
  • 5th ray is longest.
  • Soft anal fin is pointed, in some cases it is prolonged and it reaches past 1/5-1/3 of caudal fin.
  • Anal fin has 3 spines which is a characteristic feature of this genus, there are 8-9 soft rays.

Pectoral-fin : -
  • Pectoral fins occur in pair, they are asymmetric, with rounded dorsal tip.
  • 5th ray is longest, reaching to above vent.
  • Pectoral-fin rays number between 13-15.

Pelvic Fin: -
  • Pelvic fin is acuminate (pointed).
  • First ray is longest.
  • The fin might be prolonged, and reaches almost to anal fin.

Caudal Fin :-

Caudal fin is sub truncate or slightly rounded.

Distribution & Habitat

Andinoacara rivulatus is found in Pacific slope from the Esmeraldas River in Ecuador to the Túmbes River in Peru.


In its native habitat,A. rivulatus feeds on small insects and other carnivorous material.
In aquarium it should be given predominately carnivorous diet.


Adult male are rosy on chest and abdomen and lower head.
Flanks(sides) are iridescent blue with dark brown or maroon spot at base of exposed portion of each scale.
There are several iridescent blue lines on front portion of head.
Gill cover has several iridescent blue spots.

Fins are dark with blue short stripes on spinous dorsal fin and there are blue spots on anal and caudal fin.
Dorsal-fin margin and posterior margin of caudal fin are orange, which again sets is apart from A. stalsbergi.
However this cannot be taken as differentiating factor between the two species as specimens with white dorsal and caudal margin have been seen in A. rivulatus also.

There are four brownish vertical bars across caudal peduncle and sides, and two short bars or blotches on head, as per standard practice bars are numbered from Caudal or tail fin.

  • Bar 1 is placed distally on caudal peduncle.
  • Bar 2+ 3 are placed below back part of dorsal fin and cover front half of caudal peduncle.
  • Bar 4 + 5 is placed above front and middle part of anal fin base (below last two dorsal-fin spines and before three soft dorsal-fin rays).
  • Bar 6 is placed across middle of side, in front of anal fin.
  • Bar 7 is placed immediately posterior to vertical from pelvic-fin insertion.
  • Bar 8 is placed below three dorsal-fin spines at the front and forward across nape. It also incorporates predorsal blotch.

There is an indistinct dark blotch above eye, narrowly separated from Bar 7 by a lighter line.
Inter spaces which separate vertical bars are yellowish, and much narrower than bars, those bordering bar 6 particularly light.
Bars 4 + 5 are often incompletely merged, indistinctly separated by lighter bar dorsally throughout.
Bar 6 incorporates a dark brown squarish blotch which is 3-4 scales wide.
The blotch covers upper half of E1 row scales, E2 row scales and all or lower half of scales in E 3 row.
Thus it extends slightly above over upper lateral line or stops at lateral line.

Bar 7 appears with a dark blotch anterior to and less distinct than that in Bar 6.
A more distinct dark blotch appears on terminating bar 8 ventrally below the beginning of the lateral line.
In some specimens blotches in Bars 7 and 8 may be contiguous.

Depending on light conditions, scales below E2 row may show reflecting distal margin.
Scale pigmentation is often indistinct, but when pronounced, it has distinct scales of lower and middle side and caudal peduncle as light, even to reflecting white or light blue, with hyaline border except for dark spot at base of each scale and overlapping margin of preceding scale, creating a pattern of dark horizontal rows of spots on lighter background.

Upper and front part of snout is grayish.
Sides of head have 2 narrow brown lines from orbital margin across pre orbital to or almost to mouth;
There is another narrow brown line, often broken up into spots posteriorly, from little posterior to orbit slanting downwards towards of mouth.
Small dark spots are scattered over gill cover: 5-6 on opercle, 3 on sub opercle, 1 on inter opercle.
There is small dark spot at dorsal tip of opercle, immediately dorsal of origin of lateral line, and one or a few in region of beginning of lateral line.

Dorsal fin is brownish with white lappets and dark brown spot at base of each lappet; corresponding markings are also present anteriorly on soft dorsal fin.
Posterior part of soft dorsal fin has 2-3 transverse rows of indistinct lighter spots.
Anal fin is pale brownish with dark brown outer margin; posterior part of fin gradually lighter, with indistinct dark spots on posterior most inter radial membranes.
Pectoral fin is hyaline; there is a dark brown blotch across pectoral pedicel.
Pelvic fin anterior margin or lappet is whitish, rest of fin pale brownish.
Caudal fin is dark brown, short vertical bar across middle of base.
Rest of fin dusky with indistinct pattern of lighter or darker small spots. Distal margin narrowly white.

Tank Size and setup:

In its native habitat A. rivulatus is found in water having ph of about 8.5 and GH between 20- 30 dh.
These fish are very well adapted to very alkaline and mineral rich in dissolved minerals.

Tank Mates:

A. rivulatus are large sized fish and should be kept in a aquarium of about 400 liters with good filtration.


Andinoacara rivulatus are dimorphic.
Colors of female are somewhat similar to males, but their iridescent stripes are pale greenish, anterior flanks have yellowish cast.
Females have a a dark brown or blackish spot covering corner of preopercle and cheek.
Andinoacara rivulatus is a monogamous substrate spawner and that both sexes share in all the duties of brood care.

The female, however, is usually the more active partner as long as the pair cares for eggs or larvae, while the male defends the spawning territory against intruders.
Like most other open brooders these cichlids deposit their eggs on a horizontal surface.
At 27 °C hatching occurs about two days post spawning, and the fry attempt swimming seven days thereafter.
The male and female fish practice long-term bi parental defense of their mobile fry.

Morphological differences with similar species.

A rivulatus is similar to A. blombergi and A. stalsbergi in having 8-12 (usually 9-10) relatively small predorsal scales in a median row, this is in contrast to other species of Andinoacara which have a median predorsal row of eight large scales.

A. blombergi

It can be distinguished by A. blombergi by larger size, wider head, lower E1 scale count as given below:

  • A. rivulatus is of larger size with SL(standard length) of 5.5 " as compared to 4.5 " of A. blombergi.
  • The scale count in E1 row, i.e the row just above lower lateral line in A. blombergi is higher at 25 compared to A. rivulatus which has 24 scales in E1 row.
  • A. blombergi has a narrow head compared to A. rivulatus.
  • The head width of A. blombergi is 17.8 % of SL, compared to 22.0 % of A. rivulatus.
  • Inter orbital space or space between eyes is much narrow in A. blombergi compared to A. rivulatus.
  • Inter orbital in A. blombergi is 10.9% of SL compared to 15.5% of SL in A. rivulatus.

A. Stalsbergi

A. rivulatus can be distinguished by A. stalsbergi by looking at scale color pattern.
A. rivulatus have scales on side with light margin and dark spot at center,
whereas A. stalsbergi has scales with light center and dark margin.

Scale Pattern A blombergi Scale Pattern A Stalebergi

Species Snapshot

Species Card

Particulars Details
Scientific Name Andinoacara rivulatus
Common Name Andinoacara rivulatus
Genus Andinoacara
Subfamily Cichlasomatinae
Geographical Origin South America: Pacific slope from the Esmeraldas River in Ecuador to the Tumbes River in Peru.
Diet Carnivore
Gender Differences Dimorphic
Breeding Substrate Spawner
Temperament Aggressive
Con Specific Temperament Highly aggressive
Water hardness Hard Gh range 15-25 dh
Difficulty Level in Aquariums 3

Morphometric Data

Particulars Details
Total Length(inches) 8.50
Standard Length(inches) 5.50

Measurements as % of Total Length

Particulars Details
Body Depth 51.30 %
Head length 37.10 %
Pre Dorsal length  %
Pre Pectoral length  %
Pre Anal length  %
Pre Pelvic length  %
Caudal Peduncle Depth 18.30 %
Caudal Peduncle Length 14.10 %
Fork length  %
Length of Last Dorsal Fin Spine 20.70 %
Pectoral Fin Length 39.60 %
Pelvic Fin Length 35.70 %

Measurements as % of Head Length

Particulars Details
Head Width 22.00 %
Snout length 11.00 %
Eye diameter 16.30 %
Pre Orbital Length 28.30 %
Inter Orbital Width 15.50 %
Pre Orbital Depth 28.30 %

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