The caterpillar from the moth Hygraula nitens lives and feeds on the aquatic plant, Ruppia sp. and has been found in saline water up to 50 ppt. It belongs to the family Crambidae which are a poorly known group of moths whose larvae live underwater. They construct a cylindrical case of plant material that can reach two centimetres in length. The adults are small triangular moths with cream, grey and brown markings. The grid squares are 1mm2.