Lesueurigobius friesii Fries's goby

(Malm, 1874)

Special thanks fot the foto to Rudolf Svensen, Norway.

Eastern Atlantic: Spain to Skagerrak and Kattegat; Mauritania (Cape Corbiero to Nouakchott).
Also in the Mediterranean (into Sea of Marmara).

Biology:
Cryptobenthic, burrowing in muddy sand or mud; often associated with a decapod crustacean Nephrops norvegicus.
Feed on polychaetes, small crustaceans and mollusks. Eggs are deposited in burrows.

Synonyms:
Gobius friesi Malm, 1874 (misspelling)
Gobius friesii Malm, 1874
Gobius friesii friesii Malm, 1874
Gobius gracilis Fries, 1838
Gobius macrolepis Scharff, 1891
Lesuerigobius friesii (Malm, 1874) (misspelling)
Lesueuria friesi (Malm, 1874) (misspelling)
Lesueuria friesi friesi (Malm, 1874) (misspelling)
Lesueuria friesii (Malm, 1874)
Lesueuria piesii (Malm, 1874) (misspelling)
Lesueurigobius friesi (Malm, 1874) (misspelling)
Lesueurigobius friesii friesii (Malm, 1874)

Jumping guard
A jumping guard prevents (nocturnal) fish from jumping out.
Wrasses, blennies, hawkfishs and gobies jump out of an unprotected tank in fright if their night rest is disturbed, unfortunately these jumpers are found dried up in the morning on carpets, glass edges or later behind the tank.

https://www.korallenriff.de/en/article/1925_5_Jump_Protection_Solutions_for_Fish_in_the_Aquarium__5_Net_Covers.html

A small night light also helps, as it provides the fish with a means of orientation in the dark!