Cryptic Sea Gudgeon, Thalasseleotris adela Hoese & Larson 1987

Other Names: Dusky Marine Gudgeon, Marine Gudgeon, Rock Goby
Male Cryptic Sea Gudgeon from Port Phillip Bay, Victoria

Male Cryptic Sea Gudgeon from Port Phillip Bay, Victoria. Source: Rudie H. Kuiter / Aquatic Photographics. License: All rights reserved

A small marine gobioid species with a slender body, an arched back tapering to a relatively long caudal peduncle, a broad rounded head with eyes set close together on top, and two separate dorsal fins. The pelvic fins are completely separate and not joined by a basal membrane, head pores are absent, and the first gill slit is closed by a broad membrane attached to the inner gill cover.

Cite this page as:
Bray, D.J. 2017, Thalasseleotris adela in Fishes of Australia, accessed 14 Jun 2024,

Cryptic Sea Gudgeon, Thalasseleotris adela Hoese & Larson 1987

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Confined to temperate waters of southern Australia, from Sydney (NSW) to Rottnest Island (WA), including Tasmania. Inhabits silty turbid waters of rocky harbours and bays from the intertidal zone to 24 m.


Dorsal fin V–VII + I, 9–10 (usually VI + I, 9); Anal fin I, 8–9 (usually I, 9); Caudal fin (segmented rays) 15–17 (usually 16); Pectoral fin 17–21; Pelvic fin I, 5; oblique scale rows on side 22-27. 

Body slender, back arched, tapering posteriorly. Head large (31‑33% SQ, slightly broader than deep, rounded on top; interorbital very narrow, distance between orbits much less than eye diameter; mouth small, oblique, reaching to below front of eyes. 

Head without scales; body covered with ctenoid scales, cycloid on belly; vertical scale rows on side 22‑27. 

Two dorsal fins, first dorsal broadly rounded, originating behind pectoral fin insertions; second dorsal inserted just behind first dorsal; anal fin originating just posterior to second dorsal fin origin; caudal fin rounded. Pectoral fins large, with rounded margin. Ventral fins beginning just in front of pectoral fin origins. Anus just before anal fin origin.


Maximum length 4 cm


Overall tan to brown, often with large white spots or clear areas on the back; a faint oblique bar at the front of the eye, and a faint vertical bar below the eye; a black vertical bar at the caudal-fin base; a small black spot at the end of the 1st dorsal fin.Males and females are somewhat sexually dimorphic in colour pattern, particularly while breeding.


Little is known of the biology of this species. The sexes are separate and fertilisation is internal. Individuals are usually seen in pairs, and males become brightly-coloured during mating. Females deposit relatively large demersal eggs onto a hard surface. Images of females depositing eggs, and the developing eggs can be seen in Kuiter (1993). 


Of no interest to fisheries or aquaculture.


This species has considerable geographical variation in numbers of vertical scale rows and pectoral fin rays, with more southerly populations having higher counts on the average than those to the north.


Thalasseleotris is from the Greek thalassa meaning 'seas' and Eleotris a genus of fish. The species name adela, is from the Greek adelos meaning 'dim' or 'obscure', in reference to the cryptic and often dark habitat of this species.

Species Citation

Thalasseleotris adela Hoese & Larson, 1987, Mem. Mus. Vict. 48(l): 45, figs 1‑4. type locality: north of Port Arthur, Tasmania.


Bray, D.J. 2017


Australian Faunal Directory

Cryptic Sea Gudgeon, Thalasseleotris adela Hoese & Larson 1987


Hoese, D.F. 2006. Eleotridae (pp. 1596-1610). In: Beesley, P.L. & Wells, A. (eds) 2006. Zoological Catalogue of Australia.Volume 35 Australia : ABRS & CSIRO Publishing Parts 1-3 2178 pp.

Hoese, D.F. 2008. Family Eleotridae (pp. 746-748). In: Gomon. M.F., Bray, D.J. & Kuiter, R.H (eds). Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp.

Hoese, D.F. & Larson, H.K. 1994. Family Eleotrididae. pp. 810-813, figs 715-717 In: Gomon, M.F., Glover, C.J.M. & Kuiter, R.H (eds). The Fishes of Australia's South Coast. Adelaide : State Printer 992 pp. 810 figs

Hoese, D.F. & Larson, H.K. 1987. New Australian fishes. Part 11. A new genus and species of eleotridid (Gobioidei) from southern Australia with a discussion of relationships. Memoirs of Museum Victoria 48(1): 43-50 figs 1-4 PDF from BHL

Hoese, D.F. & Roberts, C.D. 2005. A new species of the eleotrid genus Thalasseleotris (Teleostei: Gobioidei) from New Zealand coastal waters. Journal of the Royal Society of New Zealand 35(4): 417-431. PDF

Gill, A.C. & R.D. Mooi. 2012. Thalasseleotrididae, new family of marine gobioid fishes from New Zealand and temperate Australia, with a revised definition of its sister taxon, the Gobiidae (Teleostei: Acanthomorpha). Zootaxa 3266: 41-52 PDF

Kuiter, R.H. 1993. Coastal Fishes of South-eastern Australia. Bathurst : Crawford House Press 437 pp.

Last, P.R., Scott, E.O.G. & Talbot, F.H. 1983. Fishes of Tasmania. Hobart : Tasmanian Fisheries Development Authority 563 pp. figs (as Satulinus sp.)

Quick Facts

CAAB Code:37429042

Depth:0-24 metres

Habitat:Reef associated

Max Size:4 cm TL


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