Marble Trout (Salmo marmoratus) is the pearl of Slovenian rivers running to the Adriatic Sea.

This special trout species behaves like a proper predator; mostly active at dawn and dusk they will only risk loosing cover when the waterlevels swell after a rainstorm. But then, on some extraordinary days, you can see them perched under the surface at the peak of the day, going after hatch like there is no tomorrow. That’s why fishing for Marble Trout is always a challenge and you can never really know what to expect. Either stripping big streamers or casting the small Mayfly, you need to adapt to the situation when after an experienced fish.

Their stunning marbled pattern in combination with large head and pectoral fins makes them a beautiful fish. When you add in the size they can reach (biggest speciment caught in the Soča River measured 120 cm and weight 22,5 kg in year 2009) and their unpredictable behaviour, you are sure in for fishing that will be hard to forget…in a good or a bad way.


Marble Trout is closely related to Brown Trout (Salmo trutta fario) and in some cases their populations naturally occur only kilometers apart, as the Julian Alps separating them are steep and form a pretty unite ridge. Since their sexual barrier has not yet evolved in the current stage of evolution of both species, they successfully breed with one another, producing fertile offspring usually referred to as hybrids in Fly fishing terminology.

In the past this knowledge was not present and due to that, there were quite some intentional (and unintentional) introductions of Brown Trout stocks into rivers of Adriatic Sea basin and despite immense efforts of fish experts, there are still some hybrid populations to be found, especially in the Vipava River.

Nonetheless the program of isolating pure Marble Trout genotype in the upper Soča catchment was successful. Fishing clubs managing this section of the river in cooperation with international scientists managed to ‘bring back’ the pure Marble trout which are now spawning in the nature and produce healthy and wild offspring.