Candidate
Black skirt tetra
Gymnocorymbus ternetzi
A large same-species school helps disperse its boisterous behaviour.
- Adult
- 5–6 cm
- Minimum
- 75 L · 75 cm
- Group
- 8
Condition-led guide · reviewed 2026-07-31
Fish for a 100 litre aquarium
A measured 80 cm footprint can support robust small communities, provided territorial and social needs are budgeted first.
Selection rules
What made the shortlist
- Measure internal water length and actual filled volume.
- Select species from one compatible water band.
- Leave capacity for adult biomass, feeding and an unexpected behaviour change.
Real photographed species
Options worth researching
Begin with the most demanding group or territory, then test any proposed companion in the builder.
Candidate
Bronze corydoras
Corydoras aeneus
A proper floor group suits a stable, fine-substrate community.
- Adult
- 6–8 cm
- Minimum
- 75 L · 75 cm
- Group
- 6
Candidate
Bristlenose pleco
Ancistrus cirrhosus
One fish can fit if wood, shelter, feeding and waste management are explicit.
- Adult
- 10–14 cm
- Minimum
- 100 L · 80 cm
- Group
- 1
Candidate
Bolivian ram
Mikrogeophagus altispinosus
A carefully planned individual or pair can anchor a floor territory.
- Adult
- 7–9 cm
- Minimum
- 90 L · 75 cm
- Group
- 1
Common mismatch
Fish to rule out for this brief
The candidates are alternatives, not one stocking list. Individual cichlid behaviour can invalidate a paper plan.
Think again
Clown loach
Chromobotia macracanthus
The adult group and 180 cm length requirement are far beyond this tank.
- Adult
- 25–35 cm
- Minimum
- 450 L · 180 cm
- Group
- 5
Think again
Bala shark
Balantiocheilos melanopterus
Its group size and continuous swimming need a much larger system.
- Adult
- 25–35 cm
- Minimum
- 600 L · 200 cm
- Group
- 5
Think again
Common pleco
Hypostomus plecostomus
Adult length and bioload exceed this footprint.
- Adult
- 30–50 cm
- Minimum
- 450 L · 180 cm
- Group
- 1