fish Easy level

Mikrogeophagus ramirezi (Myers & Harry 1948)

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Mikrogeophagus ramirezi is a freshwater fish native to Venezuela and mainly spread across the Orinoco river basin. This region includes a highly biodiverse system of tropical savannah grasslands, seasonally-flooded plains and forests between Venezuela and Colombia. There are well-defined annual weather patterns, with wet and dry seasons and high temperatures all year round.

Mikrogeophagus ramirezi are little, colourful fish, that usualy do not exceed 4 cm in lenght. It can be easily kept in a home aquarium, provided that the biotope tank is at least 60 cm.

Distribution: Orinoco River basin – Colombia and Venezuela.

Submitted by
Heiko Bleher
4.1360731, -72.9946823
Geographical region
South America
Drainage Basin
Rio Amazonas
River catchment
Rio Meta
Water body type
Water body name
Water body part
Water body course
Lower course
Water body: tributary of
Tributary name
Type locality
Orinoco system, Venezuela.
Conservation status/IUCN Red List
Not Evaluated (NE)


Water Chemistry

Water information

Water type
Fresh water
Water color
Clear water
Water transparency
Concentration of sediments
Water temperature
27-30 °C
Water flow/curent

Chemical parameters

Dissolved Oxygen


Standard length
3.4 cm
Water volume (min. aquarium)
54 l
Social behaviour
Lives in pair
Behaviour description

Mikrogeophagus ramirezi is a benthopelagic species that has been widely used in behavioural studies. This is a species that lives in pair and is pacific.

This species is not recommended for the general community aquarium, since it requires pristine water quality and is a poor competitor, although it can be paired with other species, if researched in depth. Groups of peaceful, open water-dwelling characids or similar are good tankmates. On the contrary, it is essential to avoid territorial or aggressive fishes.

Juveniles are gregarious but once they reach sexual maturity they start to form pairs, each of which will command a “territory” when breeding.

Aggression grade
Day active
Sexual dimorphism

Adult males grow larger than females, have slightly more extended fins, and are more intensely coloured. Most females possess a pinkish patch on the belly, although this may not be the case in some ornamental strains.

Nutrition in Nature

As a benthopelagic species, Mikrogeophagus ramirezi normally take mouthfuls of substrate which are sifted for edible items; the remaining material is expelled via the gill openings and mouth. They also browse solid surfaces and snatch items directly from the water column.


Breeding tank set-up

This species is not fussy with décor. A natural-looking tank might be arranged with a soft, sandy substrate, roots and branches that provide plenty of shady spots and caves, one or two flat rocks to provide potential spawning sites. Dried leaf litter, other than further emphasising the natural feel and providing a secondary food source for fry, spur the growth of beneficial microbe colonies and the releas of tannins and other chemicals with their decomposition. Aquatic plants and ferns that can be included in a tank are:

Some wetland plants can be added to the biotope set-up: Panicum repens, Luziola subintegra, Leersia hexandra, Landoltia punctata, Hymenachne amplexicaulis.

Filtration and water flow should not be very strong, but this species requires pristine water conditions. It is best to do regular water changes of 10-15% than do very large changes once in a while.

Mikrogeophagus ramirezi should never be added to new or biologically immature aquaria. When conditions deteriorate, it can show eroding flesh around the head and lateral line pores.

Nutrition parents

In the biotope aquarium, Mikrogeophagus ramirezi should be offered a variety of live and frozen fare such as bloodworm, ArtemiaDaphnia, grindal worm, etc., along with good quality, small-sized, sinking dried foods.

Mating type
Spawning behaviour

This species is a biparental substrate spawner and is best bred in a dedicated set-up with no other fishes present. The eggs can be tricky to raise and easily develop fungus or fail to develop unless the water is very clean and of low hardness, however. The eggs are normally laid on a solid surface and spawning occurs. Female cares for eggs and larvae.

If the adults are included in a community tank, it is best to remove either tankmates or eggs when you wish to raise good numbers of fry.


Breeding habits
Hatching period
2-3 days
Number of eggs in average
up to 200
Parental care
Fry number
Nutrition fry

During the incubation of 2-3 days after which the fry remain immobile for a further 5 days, fry do not require any supplementary food. Once free-swimming, they should be fed with microworm, infusorian and other microscopic foods for the first 2-3 days, after which larger foods such as Artemia nauplii can be introduced. The addition of dried leaf litter can also provide a secondary food source for fry.

Notes on reproduction

If you want to parent raise the fish, it is strongly suggested to keep them in a species tank with no other fish of any sort. The tiny Ram fry seem to be eagerly eaten by almost every other fish and it is very rare for any fry to survive in a mixed species tank. Also, Rams can be slow to spawn. If your fish just don’t seem to want to spawn try giving them high quality live food for several weeks followed by a large water change and raise the temperature a couple of degrees. This will often stimulate a spawn.