After we successfully and actively cooperated in the organisation of the monitoring and subsequently the production of the propulsion units and in the development of the new and powerful Yanmar NCL-LX robot for the cleaning of cages of hatcheries the time came for its presentation to other fish farmers from the Mediterranean where Navela is the sole distributor. Adding to that is the fact that in Croatia two such serial robots are already working, one at white fish hatcheries and the other at tuna hatcheries. First in line came the Spanish who produce around 285,000 tonnes of farmed fish per year in their part of the Mediterranean and are by far the largest fish farmers in the Mediterranean, and they also have hatcheries in Greece. For fish farmers centred in Borriana, not far from Valencia, we organised a personalised week-long demonstration of the cleaning of 38m-diameter large cages for white fish which are located practically out in the open sea. The presentation in which three members of the Navela team participated consisted of the preparation of the robot for work, previous training, becoming acquainted with all the system components and the cleaning of the cages itself that lasted two days. The feedback was excellent. It was shown that the large Yanmar robots are very well adapted to the operational needs of the fish farmers. They are simple to use, they are easy to handle by existing teams who look after the supply and maintenance of hatcheries, and at the same time after the initial investment they contribute significantly to savings in the cleaning of cages and their better maintenance. The NCL-LX robot significantly shortens the cleaning time; the cleaning is more efficient and the quality is better; fuel is saved; cleaning in the cages with the robot improves the flow of the sea which favours the growth of the fish and so production improves; the robot enables online monitoring of the cage; just one member of staff controls it and the handling itself is simple and stable.