It is orange-brown to olive-brown with very variable dark brown markings that can be speckles, spots, or irregular bands, and its skin is heavily dusted with gold.

[3] This species lives only in eastern waterways of Otago, in wetlands and small streams that flow into the Taieri, Tokomairiro and Waipori rivers and below Lake Mahinerangi.

[6] Its original distribution was likely much larger, but trout species have eradicated it in all but the headwaters which make up its current home range.

[6] Unlike the more well-known 'whitebait' Galaxias species, G. eldoni is not diadromous; its entire life is spent in fresh water.

Because G. eldoni lays very few eggs and has large, poorly dispersing fry, it is vulnerable to predation by introduced trout.

[1] The building of irrigation canals has allowed the closely related species Galaxias pullus to invade its range and hybridise with it.