Pseudanos trimaculatus – Threespot Headstander

Pseudanos trimaculatus of in het Nederlands de Drievlek Kopstaander is een redelijk zeldzame verschijning in de hobby. Advies: houdt ze in een grote groep!

Pseudanos trimaculatus – Threespot Headstander

Pseudanos trimaculatus was first described by Kner in 1858 as Schizodon trimaculatus. Later they have belonged to the Anostomus genus for a very long time. A total of four species are currently placed in the Pseudanos genus: Pseudanos gracilis, Pseudanos inrinae and Pseudanos winterbottomi.

The genus name Pseudanos is derived from ancient Greek pseudes and means fake. Trimaculatus means with three spots.

This species first appeared in the aquarium hobby around 1913. However, at present this species is rarely offered.


Like all its other family members, Pseudanos trimaculatus is elongated and somewhat round in shape. They also have the characteristic upward mouth. The color is a silver brown with red in the fins and around the mouth. Two black spots are usually visible on the flank. A third spot is sometimes visible on the opercolum. They can reach a maximum length of around 16 centimeters. In appearance they are very similar to Petulanos plicatus (formerly called Anostomus plicatus).

The difference between the sexes is not clearly visible.

They are schooling fish that should be kept in a group of at least 8 specimens. Fish that are kept solitary or in a too small group do not feel at ease. They are then susceptible to diseases, become shy or aggressive and languish.


The distribution area of the Threespot Headstander is large. They occur in Argentina, Brazil, Ecuador, Guyana and Peru. Threespot Headstanders inhabite the Amazon basin, Rio guaporé in Brazil and Rio Essequibo and Rio Rupununi in Guyana, among other places. You can usually find them in groups of 10 to 50 specimens in deeper water. They are often found together with Leporinus species such as Leporinus frederici.


The diet of Pseudanos trimaculatus consists mainly of plants and algae in the wild. In addition, they occasionally also eat some invertebrates. In the aquarium you have to make sure they get enough vegetable food. You can feed them with a mixture of live and frozen food, but make sure to add sufficient vegetable material. This includes algae wafers, spirulina flakes, blanched spinach, lettuce, cucumber, zucchini etc.

Pseudanos trimaculatus aquarium

Because this species is a bit larger and must be kept in a group, a spacious aquarium from 150 centimeters is recommended. Decorate the aquarium with (filter) sand on the bottom. Place some wood and branches for decoration and to break the lines of sight. Make sure the aquarium is properly closed, they are excellent jumpers!

Soft leaved plants do not last long in an aquarium with Pseudanos trimaculatus. Soft leaves soon disappear into the stomach of the Threespot Headstander. If you want to keep plants, use tough species such as Anubias and Java Fern. These are more resistant to the continuous grazing of this species. They will also graze on algae. If you buy this species it is better to wait until the aquarium has matured somewhat and has some algae for them to feed on.

The water may have a temperature of around 23 to 27 degrees. They like slightly more acidic to neutral water with a pH of 6.0 to 7.5.

Keep them in a group of at least 8 specimen to divide the aggression. They usually leave other species alone. You can therefore usually combine them well with characins, armored catfish, peaceful cichlids, Corydoras species and the like. It is better not to combine them with other Headstanders or, for example, Angelfish with long fins that they can nibble on.

Breeding Pseudanos trimaculatus

Nothing is known about breeding Pseudanos trimaculatus in captivity.



John de Lange

Copyright images

Mergus Aquarien Atlas – auflage 8 – pagina 236

Additional information






Anostomus trimaculatus, Schizodon trimaculatus

Common name

Threespot Headstander

First described by

Rudolf Kner


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