Gas bubble disease in captive Golden Trevally: Pathological insights and needs for life support system and water quality management

Objective This study aims to elucidate the cause of mass mortality in Golden Trevally Gnathanodon speciosus at an aquarium and reports the first instance of gas bubble disease (GBD) in the species. Identifying the factors leading to this mortality event is intended to propose preventive measures for avoiding similar occurrences in the future. Methods This case study involved the examination of Golden Trevally displaying symptoms of GBD, including abnormal swimming behavior, lethargy, and visible gas bubble formation in the cornea, aqueous humor, and oral mucosa. Necropsy and histopathology were conducted to assess the internal accumulation of gas bubbles in tissues. The etiology was investigated by analyzing the total dissolved gas (TDG) levels and inspecting the integrity of the water circulation system for structural defects. Result The affected Golden Trevally exhibited significant symptoms of GBD. Necropsy and histopathology confirmed the presence of gas bubbles in various tissues throughout the body. The analysis suggested that TDG supersaturation was caused by excessive microbubble formation due to structural defects in the water circulation system. Conclusion This case highlights the importance of practical TDG monitoring and maintaining system integrity to prevent GBD in aquaculture. Effective management of TDG levels is crucial to safeguarding the health of captive aquatic species. Impact statement In artificial aquatic breeding environments, high total dissolved gas concentrations can cause gas bubble disease and subsequent mass mortality, even if the dissolved oxygen concentration is normal. Therefore, it is crucial to closely monitor the environmental conditions.