The spread of the Neolithic way of life from its centers of origins remains one of the central topics of archaeological research, with ongoing debates about the importance of economic, demographic, and cultural changes in the transition. The Southern Caucasus, while close to one area where agriculture emerged, has remained understudied regarding this spread. Here, information about the role of fish, a topic that has been almost completely neglected until now is presented. Fish remains are scarce in this region. Moreover, isotope analyses seem to indicate that freshwater fish were not an important food source. For the first time, fishbones have been found in larger quantities at the site of Aruchlo I from some layers in ditches. It is the largest assemblage of fish bones safely dated to the sixth millennium BC in the South Caucasus. The interpretation of these finds is not straightforward due to the lack of other comparable finds and the absence of fishing gear. Fishing appears to have been conducted in the waters close to the settlement. It is unclear if fishing was a year-round activity, although the way these bones were concentrated in different layers in the ditches suggests that this was not the case. We think that the bounteous catch of spawning fishes at certain times of the year can be linked to special social events like feasting, showing the importance of a food resource that is usually greatly underrepresented archaeologically. Introducing more precise recovery methods for animal remains at other excavations will hopefully refine our understanding.