The infralittoral fish assemblage was investigated inside the temperate Zrmanja river estuary, Adriatic Sea. The specimens were caught using a beach seine at three stations and four times over the year. A total of 10 035 individuals, belonging to 47 species and to 17 families were represented in the catch, out of these Atherina boyeri (60.3%), Symphodus ocellatus (14.4%) and Pomatoschistus marmoratus (7.5%) were most abundant, comprising 82.2% of the total catch. Marine and estuarine species represented 89.6 and 10.4%, respectively, while freshwater species were not observed in samples. Differences in fish assemblages were observed with respect to sampling dates and stations mostly due to different temporal and spatial distributions of juvenile fish settlers. Juveniles of open sea spawners (L. mormyrus, P. erythrinus) were found with increased distance from the river mouth. As they progressively grow, they disperse throughout the estuary. Juveniles of resident species (Pomatoschistus sp.) stayed closer to the river mouth. Permanent estuary residents comprised 11 species, 33 species were opportunists and the remaining 3 were transients. The data thus show that even in small temperate estuariesthe characteristics of river inflow have the potential to alter spatio-temporal patterns in infralittoral fish assemblages.Infralitoralne zajednice riba su proučavane na području ušća rijeke Zrmanje, u Jadranskom moru. Jedinke su ulovljene malom obalnom mrežom potegačom na tri postaje, u četiri uzorkovanja tijekom jedne godine istraživanja. Ukupno 10 035 jedinki svrstanih u 47 vrsta i 17 porodica, je bilo zastupljeno u uzorku, od čega su Atherina boyeri (60,3%), Symphodus ocellatus (14,4%) i Pomatoschistus marmoratus (7,5%) bile najzastupljenije vrste, sačinjavajući 82,2% od ukupnog uzorka. Prave morske i estuarijske vrste riba su bile zastupljene s 89,6, odnosno s 10,4%, dok slatkovodne ribe nisu uopće ulovljene. Utvrđene su prostorne i vremenske razlike u zajednicama riba zbog različite vremenske i prostorne raspodjele nedoraslih riba. Nedorasle jedinke onih vrsta koje se mrijeste u otvorenom moru (L. mormyrus, P. erythrinus) su nađene s povećanom udaljenošću od samog ušća rijeke. Kako su navedene jedinke rasle, tako smo ih nalazili različito rasprostranjene na širem području ušća. Nedorasle jedinke rezidentnih vrsta (Pomatoschistus sp.) su ulovljene blizu samog ušća. Stalni su estuarijski rezidenti sačinjavali 11 vrsta, 33 vrste su bile oportunisti, a preostale 3 tranzitne vrste. Podaci pokazuju da čak i mali estuariji umjerenih geografskih širina imaju potencijal pojačati prostorno-vremenske razlike u zajednicama infralitoralnih riba
