October the 20th, 2025 – This country is full of waterways and important rivers, but did you know that there’s a Croatian river where trout grow 7 times faster than anywhere else?
As Putni kofer/Martina Hrupic writes, stretching along through the hinterland of Velebit, the gorgeous Gacka River is one of the most famous and most beautiful Croatian rivers. Its crystal clear water, through which every single little aquatic weed can be observed, its banks covered in greenery, and its beautiful springs and mills are its main assets that have turned it into one of the main attractions Lika has to offer. The Gacka River is one of the Croatian freshwater areas that cannot be missed.
The Gacka River is 61 kilometres long, including its tributaries. It flows relatively slowly, and its water is so incredibly clear that you can see everything in it, and it’s eternally very cold. During the scorching Croatian summer it averages a mere 11 degrees, and in winter, it drops down to just eight. It’s also exceptionally shallow, ranging from one metre to a maximum of just 10 metres deep. Rather unlike other rivers that are known for their instability, the Gacka has fascinated all those who have studied it with its pure constancy. It is quite uniform in terms of water quantity and its temperature.
the river still retains an air of mystery
The first explorations of the Gacka and its world, hidden away from us, began back during the second half of the last century. Despite this extensive research, it still represents a great unknown. It’s believed that more than half of its underground channels remain entirely unexplored by humans. In speleological terms, the most famous area of them all is Majerovo vrelo (spring).
This spring, or rather, as it is called, vrilo, along with Tonkovića vrilo, is one of the most famous sources of the Gacka River. Even today, it’s beautifully adorned with the so-called skele, the local name for old mills that once formed groups of mills centuries ago. Some of them are still in operation today, but most have since turned into more of a tourist attraction than the focal point of social and economic life as they once were across the entire Lika region.
This stunning Croatian river is also very well known in some circles for its inhabitants, primarily its rapidly growing trout. Its water is extremely rich in oxygen, which is favourable for this type of freshwater fish. Apparently, research has even shown that for some reason, in this particular Croatian river, trout happens to grow 5 to 7 times faster than in any other body of water of that type. This means trout from the Gacka can weigh up to five kilograms.
the gacka plain – inhabited since the stone age
The Gacka River provided most of what was necessary to the local people who have tied their lives to it on many levels throughout the centuries. It also came to their rescue in the harsh Lika winters, when locals needed to feed their livestock. This Croatian river is very rich in aquatic vegetation that the locals used to utilise, sailing along it in small boats to harvest it for their animals.
The largest town connected to the Gacka River, but also to the Gacka Valley itself, is the well known Otočac. It was founded at the place where the river itself forks. People have lived in and around the Gacka Plain for a long time now, more specifically since way back in the Middle Stone Age. The oldest evidence of human life there, dating back to that period, was found in the nearby Pećina cave.
This Croatian river is a treat for the eyes as much as it is for anyone who happens to catch a trout from it. It’s an atypical destination where you can relax and enjoy the beautiful nature that Lika so effortlessly abounds in.
Subscribe to our newsletter
the fields marked with * are required
