The ecnomid caddisfly larvae have hardening (sclerotisation) on each of the 3 thoracic segments. Unlike the hydropsychids, there are no gills under the abdomen. In Zelandoptila the thoracic sclerotisation is more complete and darkly pigmented than in the related Ecnomina.
They are most likely to be found (though usually in low abundance) in bush-covered gravelly streams.
Zelandoptila larvae are thought to be predators, feeding on other stream invertebrates.
Zelandoptila larvae can be an indication of good water quality, particularly if they are found along with a range of mayfly and stonefly taxa. They have tolerance values of 8 (hard bottom sites) and 7 (soft bottom sites).