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Aequidens pallidus

Aequidens pallidus
Image Credit: wikipedia


Aequidens pallidus is a moderately large fish of about 6 " found in Rivers Negro,Amazonas, and Prague, in Brazil, South America.


(Click for details of Cichlid taxonomy)

Aequidens pallidus was first described by Heckel in 1840 and was named as Acara pallidus.
Later on the classification was revised and has now been placed in Genus Aequidens and subfamily Cichlasomatinae.
The Genus "Aequidens" is derived from Latin words, equips+equal+dens(teeth), which roughly translates to "Fish with equal teeth".
The Species name is derived from latin word pallidus, which means "faded", referring to its colors.


Aequidens pallidus is somewhat moderately large fish with standard length about 8".
It has a typical tri serial pre dorsal arrangement of scales of Aequidens with E1 scales 25 or 26.
The pectoral fin is large, 36-46% of SL(standard length).

It is somewhat similar to A. tubicen having a wide light spot anterior(before) caudal spot.
Lateral band is high on the side, mid spot is positioned towards posterior(back) and vertebral count is high at 27.
However it can be differentiated from A. tubicen as per below:

  • It has a supra orbital spot( just above eye) which is absent in A. tubicen.
  • A normal cheek spot whereas A. tubicen has a spot on preopercular (near nostril).
  • The posterior part of lateral band is continuous unlike A. tubicen where it is divided into blotches.

Aequidens pallidus is also similar to A. diadema, and can be distinguished by having more scales, E1 scale row count is 25-26 instead of 24, dark margin on dorsal flank scales are narrower , mid lateral spot is placed more posterior (behind).

It is known to live for 8-10 years.

Distribution & Habitat

Aequidens pallidus is found in South america, Middle and lower River Negro, River Preto da Eva, River Puraquequara and River Uatumă drainage.
It has been collected from both running water and still streams but is mostly restricted to black and clearwaters.
It is benthopelagic or swims above river/stream bed at depths of about 1-3 m in black water rivers.


It is a carnivorous in nature, and eats small fish, deitrus.

Keeping in Aquarium

Water Parameters

Aequidens pallidus is found in running waters of Rivers Negro,Amazonas, and Puraquequara in Brazil with a ph of 4.5-6 and dh range 3-9.

Tank Size and setup:

Aequidens pallidus are moderately large sized fish and should be kept in a aquarium of about 300 liters with good filtration.
A sand bed of fine sand and many shelters with rocks and driftwood are ideal for this fish

Tank Mates:

They are not very aggressive but can be very aggressive to others of same species.
At breeding time the aggression increases.
Small fish should not be kept with them as it will be eaten.


Aequidens pallidus are dimorphic, and reach sexual maturity in about 9-11 months.
They lay eggs on flat surfaces and practice brood care.
Both parents take care of eggs and larvae.
The females are smaller and will clean a piece of flat rock and lay 500-600 eggs.
The eggs will hatch after 2-3 days and fry will be free swimming within a week.
Fry can be fed brine shrimp.
The pair will be ready to breed again if the fry are removed early.

Species Snapshot

Species Card

Particulars Details
Scientific Name Aequidens pallidus
Common Name Double Spot Acara
Genus Aequidens
Subfamily Cichlasomatinae
Geographical Origin Amazon River basin, in the middle and lower Negro River, UatumĂŁ, Preto da Eva, and Puraquequara rivers.
Diet Carnivore
Gender Differences Dimorphic
Breeding Substrate Spawner
Temperament Peacefull
Con Specific Temperament Mildy aggressive
Water hardness Soft, dh range 3-9
Difficulty Level in Aquariums 3

Morphometric Data

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

Measurements as % of Total Length

Particulars Details
Body Depth  %
Head length  %
Pre Dorsal length  %
Pre Pectoral length  %
Pre Anal length  %
Pre Pelvic length  %
Caudal Peduncle Depth  %
Caudal Peduncle Length  %
Fork length  %
Length of Last Dorsal Fin Spine  %
Pectoral Fin Length  %
Pelvic Fin Length  %

Measurements as % of Head Length

Particulars Details
Head Width  %
Snout length  %
Eye diameter  %
Pre Orbital Length  %
Inter Orbital Width  %
Pre Orbital Depth  %

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