10 decision guides

Start with the aquarium you have, not the fish you saw.

Shortlists built around tank length, adult size, water and social needs. Each candidate links to the full reviewed profile.

Condition-led shortlist

Fish for a 40 litre aquarium

A short, welfare-first list for compact mature aquariums, where footprint and group size remove many shop favourites.

See the shortlist →

Condition-led shortlist

Calm small species can work in this common starter size when the full social group and horizontal length fit.

See the shortlist →

Condition-led shortlist

This volume opens several classic community species, but group size and a 75-80 cm swim length remain decisive.

See the shortlist →

Condition-led shortlist

A measured 80 cm footprint can support robust small communities, provided territorial and social needs are budgeted first.

See the shortlist →

Condition-led shortlist

Species that can use mineral-rich water without forcing soft-water fish through chronic compromise.

See the shortlist →

Condition-led shortlist

A shortlist for naturally low-mineral water, organised around calm shoals and appropriately sized centrepieces.

See the shortlist →

Condition-led shortlist

Fish that can be planned below standard tropical heat, with oxygen and seasonal room temperature considered.

See the shortlist →

Condition-led shortlist

Floor area, social group and territory matter more than spare litres when choosing bottom dwellers.

See the shortlist →

Condition-led shortlist

Resilient species still need full groups, suitable water and enough length to show natural schooling behaviour.

See the shortlist →

Condition-led shortlist

Small shop specimens and misleading common names conceal adults that need large groups, territories or long swimming runs.

See the shortlist →