EcoWorld Aquarium is a small wildlife centre on the Picton foreshore, focused on the native marine and freshwater species of the Marlborough region. It has tanks of native fish, eel feeding sessions, a tuatara enclosure, and an injured-bird recovery wing that the public can visit.
It is not a large aquarium — allow an hour at most — but the focus on local species and the rehabilitation work makes it more interesting than its size suggests. The eel feeding is the highlight; longfin eels can grow to two metres and live for a century. Admission is around NZ$20; open daily.