Astatheros robertsoni Care Guide: Tank Size, Diet & Temperament

Central American cichlids span a huge size and temperament range — from 3-inch dwarf species to 12-inch tankbusters — and Astatheros robertsoni sits usefully in the middle of that range, making it a good case study for what "medium-sized cichlid" actually means in practice.

Direct Answer: A Medium-Sized River Cichlid From Chiapas

Astatheros robertsoni is a 6-8 inch Central American cichlid native to Pacific slope river systems in Chiapas, Mexico, sitting between dwarf species like Amatitlania nanolutea and the largest Central American cichlids in both size and tank requirements. A 55-gallon tank is a reasonable minimum, ideally with moderate water flow reflecting its river origins. Its diet includes a meaningful plant-matter component, more so than purely carnivorous cichlids. Temperament is moderately territorial — more assertive than dwarf species, but less extreme than the largest Central American cichlids.

Native Range and Habitat

Astatheros robertsoni comes from Pacific slope river drainages in Chiapas, Mexico, and nearby areas — flowing water habitats rather than the slower lakes, ponds, or backwater pools that some other cichlid species favor. This river origin is worth reflecting in tank setup: moderate water movement from filtration output, rather than a completely still tank, is closer to what this species naturally encounters.

Tank Requirements

A 55-gallon tank is a reasonable minimum for an adult:

• Moderate flow from filtration, reflecting river origins
• Sand or fine gravel substrate suited to digging behavior typical of many Central American cichlids
• Rockwork or driftwood for territory definition — see our driftwood cichlid tank guide for general considerations, scaled to this species' size and activity level
• Strong filtration, as with most medium-to-large cichlids

Diet: More Plant-Inclusive Than Many Cichlids

One of the more practically relevant traits of Astatheros robertsoni (and several related Astatheros species) is a meaningful plant-matter component in its natural diet — more grazing-oriented than purely carnivorous cichlids. In aquarium terms, this points toward omnivore-formulated cichlid pellets as a better staple than high-protein carnivore formulas, plus occasional blanched vegetables. It also means live plants are at real risk of being grazed or uprooted — a consideration for anyone hoping to combine this species with a planted setup.

Temperament: The Middle of the Spectrum

Astatheros robertsoni is territorial and moderately aggressive — more so than a dwarf species like Amatitlania nanolutea, but generally less extreme than the largest, most combative Central American cichlids, including hybrid lines like the red tiger motaguense. This "middle ground" makes it a reasonable next step for keepers moving up from smaller territorial cichlids without diving straight into the most aggressive end of the hobby — though "moderate" still rules out small or peaceful tankmates. Realistic tank mates are other medium-to-large, robust cichlids able to establish their own territory.

Quick Reference

• Astatheros robertsoni reaches roughly 6-8 inches — medium for a Central American cichlid
• Native to Pacific slope river systems in Chiapas, Mexico
• 55+ gallons minimum, with moderate flow reflecting river origins
• Diet includes a notable plant-matter component — omnivore pellets preferred over carnivore formulas
• Live plants are at risk of grazing/uprooting from this species
• Temperament sits between dwarf cichlids and the largest, most aggressive Central American species
• Tank mates: other medium-to-large, robust cichlids only