Get a Huge Tank

All fish

Threespot Headstander

Pseudanos trimaculatus

Freshwater South America

The threespot headstander is a captivating characin that swims tilted forward at a characteristic 45-degree angle. It spends its time browsing aufwuchs and organic matter from sunken timber. Keepers must remember it eats tender aquatic plants and frequently nips trailing fins, so pairing it with short-finned, robust tankmates is crucial.

16 cm adult length, drawn to scale. torpedo body.

Try it in the planner Opens a tank sized to its minimum with 6 fish added.

What it needs

ItemValueBecause
Adult length 16 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 300 L, at least 120 cm long estimated The least water and floor length this species is kept in for good, as a single fish or smallest group.
Extra water per added fish 30 L estimated What each further fish adds once the minimum is met.
Waste load Class 3 of 5 estimated How much waste an adult makes against its size. Feeds the Load check.
Temperature 23 to 28 C Stock sharing a tank need overlapping ranges.
pH 6 to 7.5 Compared with tankmates in the Water check.
Hardness GH 4 to 14, KH 2 to 8 Degrees of general and carbonate hardness.
Flow Medium Low-flow fish are stressed in a strong current.
Light Moderate Matched to the lighting class on the needs sheet.
Group size At least 6, ideally 8 Kept alone or in small numbers it hides, fades or turns on tankmates.
Temperament Semi-aggressive Territorial: weak.
Swims in All levels Fish that use different levels share a tank more easily.
Lifespan About 8 years A fish is a long commitment.
Experience Some experience helps A guide to how forgiving the species is of mistakes.
Jumps Yes Keep the tank covered.

Tags marked estimated are judged from the size and habits of the species rather than measured, so treat them as a sensible default.

Diet and tank layout

Threespot Headstander is an herbivore that swims in all levels of the tank. It eats or uproots plants, so choose hard-leaved species or none. Give it plenty of cover. It nips fins.

Tankmates

Works with

No close matches in the data. Check the pair tool.

Depends

Avoid

Compare any two fish on the compatibility page, or print the equipment for a stock on the needs sheet. How this is worked out: the method.