'aquariist' originates from Modern English, specifically formed from 'aquarium' + the agent suffix '-ist', where Latin 'aqua' meant 'water' and '-arium' denoted a place for something.

'aquariist' was formed in English by adding the suffix '-ist' to 'aquarium' (from Modern/Latin 'aquarium'); 'aquarium' itself came from Latin 'aquarium' (a place for water) derived from 'aqua' meaning 'water'.

The component 'aquarium' originally referred to a container or place for water; over time the derived term 'aquariist' came to mean 'a person who cares for aquaria' rather than the place itself.