'fishkeeper' originates from Modern English as a compound of 'fish' and 'keeper', where 'fish' ultimately comes from Old English 'fisc' meaning 'fish' and 'keeper' is derived from the verb 'keep' (Old English 'cēpan') meaning 'to hold, keep'.

'fishkeeper' was formed in Modern English by combining the noun 'fish' (Old English 'fisc') with 'keeper' (from Old English 'cēpan' → Middle English 'keepen'/'keep'), evolving into the compound noun 'fishkeeper'.

Initially, 'keeper' meant 'one who keeps, holds, or guards' (a guardian or custodian); over time the compound 'fishkeeper' came to mean specifically 'a person who keeps and cares for fish (often in aquariums or ponds)'.