<p>Chemical communication between predators and prey plays a crucial role in aquatic ecosystem dynamics. The development of mosquito larvae is altered by fish-released kairomones, but it is unclear if this effect is dependent on fish microbiota. We investigated the role of fish microbiota in kairomone production by manipulating the bacterial community structure of the mosquitofish <i>Gambusia affinis</i> using low-concentration antibacterial treatments. We compared development time and survival of <i>Culex laticinctus</i> larvae reared in water with chemical signals from treated fish, untreated fish, or fishless controls. Mosquito larvae exposed to cues from untreated fish developed significantly faster than those in both fishless control water and water with signals from treated fish. Our findings demonstrate that fish microbiota is essential for producing fish-released kairomones that accelerate mosquito development, likely through specific bacterial strains or community interactions. This microbiota-mediated chemical communication has important implications for biological control programs using larvivorous fish and highlights the need to consider microbial communities when designing aquatic pest management strategies. Understanding these mechanisms could improve the effectiveness of fish-based mosquito control by optimizing microbial conditions that enhance predator–prey chemical signaling.</p>