The Danube River, Europe's second-longest waterway, has become a symbol of this summer's brutal drought. In northern Serbia, a side channel near Novi Sad has shriveled to a few stagnant ponds, leaving small boats stranded on cracked earth. Fisherman Dusan Jovanovic watches the fish circle in the shallow, overheated water. "This is all we have, these two little ponds that are full of juvenile fish," he said, his voice carrying the weight of desperation. The water temperature has climbed above 30 degrees Celsius (86 degrees Fahrenheit), and Jovanovic fears the worst. "If they start to die, they will all die at once." His concerns echo across a region where persistent drought and record-breaking heat have upended lives and livelihoods. From a lake in Slovenia to fish farms in Bosnia, Romania, the Czech Republic, and Hungary, the toll is mounting. The fish industry alone faces millions of euros in losses, compounding existing problems with energy shortages, water supply disruptions, devastated crops, and reduced river traffic. Governments and businesses, many of which were unprepared for this year's intensity, are now scrambling to devise strategies to cope with future extreme weather events that scientists attribute to human-driven climate change. In Hungary, the national meteorological service reports that nearly 99% of the country's land is under severe or extreme drought conditions. Desertification, a process where vegetation retreats due to high heat and low rainfall, now threatens vast stretches of the Great Hungarian Plain. The country's roughly 27,000 hectares (67,000 acres) of fish ponds have been among the hardest hit. According to the Agriculture and Food Economy Ministry, 1,588 hectares (3,924 acres) of those ponds have completely dried out, resulting in the deaths of nearly 280 metric tons of fish at 20 farms. The estimated revenue loss stands at 1.3 billion forints ($4.2 million). Producers warn that replacing lost fish could take years. In some cases, operators were forced to drain one pond and divert its water to save fish in another, the Hungarian Aquaculture and Fisheries Inter-branch Organization noted in early August. Across the border in Romania, fish farmers, particularly those cultivating carp, are still reeling from severe droughts in 2023 and 2024. Catalin Platon, president of the ROMFISH National Association of Fish Producers, explained that carp production relies on a three- to four-year cycle. "So what we lost in 2023 has had an impact every year since," he said. He added that water-use policies during previous droughts prioritized irrigation for agriculture, "leaving us with no water for the fish." In the Czech Republic, fish farmers have implemented emergency measures, including reducing or suspending feeding to lower oxygen consumption, aerating ponds, or draining them when necessary. Officials from the Czech Fishing Association say sustained rainfall could ease the immediate crisis, but long-term solutions are needed to retain more water in the landscape. Jan Sokolik, a technician at the Rybarstvi Trebon fishery, noted that "some ponds that were actually low on water have already been fished, but they were all marginal ponds." He added, "Now we're just starting to plan what to do with the big ponds." In Bosnia, Veljko Budjen owns a trout farm near Trebinje in the southeast. He described how hot, dry summers have brought serious problems to the mountainous country, known for its trout restaurants. "Trout is a cold water fish, which requires cold water with a lot of oxygen," he said. "So during the summer you are forced to reduce trout production and feeding so the business can just barely survive." One option, he noted, is to add liquid oxygen to the water during the summer months. Otherwise, "you wait for the first rain." In eastern Slovenia, emergency teams have been pumping water into Lake Pristava, a popular fishing spot, to prevent a mass fish suffocation from lack of oxygen and an overgrowth of water chestnut covering the lake's surface. Firefighters have pumped in 8 million liters (2 million gallons) of water, but they still fear it may not be enough. "We are surprised that any fish has survived at all," Danijel Fras from the Pesnica Lenart Fishing Association told public broadcaster RTV Slovenia. In Serbia, the only solution for the endangered fish in the Danube side channel seems to be relocation. Jovanovic, the Serbian fisherman, summed up the pervasive sense of alarm: "The temperatures this year are extreme. No one can remember anything like this."