More fish have been found dead at a Wellington marine centre a day after it was targeted by vandals.
Staff at the Island Bay Marine Education Centre discovered on Saturday that pool treatment tablets, toxic to most marine life, were dropped into an outdoor storage tank.
Up to 80 fish - about half the centre's exhibits - were killed.
Volunteers and the Fire Service worked all Saturday to move the remaining fish to uncontaminated water while they flushed the tank.
However manager Julian Hodge said when he looked into the tank on Sunday he found more dead fish.
He said over the two days many larger fish had survived but most of the small ones succumbed to the toxin.
Mr Hodge said the storage tank was relatively unprotected because staff never contemplated anyone would do such a thing.
The centre has now bolted and padlocked the cover of the tank and is considering installing security cameras.