Disease Occurrence and Water-Quality Associations in Quarantined Sebae Clownfish (Amphiprion sebae)

Abstract

The present study investigated the occurrence of major diseases in the Sebae clownfish, Amphiprion sebae, collected from the southern region of Palk Bay and maintained under quarantine conditions, with emphasis on the relationship between disease occurrence and selected physicochemical parameters of the culture water. Fish were maintained in recirculatory aquaculture systems and monitored for three months from January to March 2022. Water temperature, salinity and pH were assessed throughout the observation period, while clinical signs associated with bacterial, fungal and protozoan diseases were recorded. Temperature ranged from 26.83 to 31.60°C, salinity from 36.00 to 38.50 ppt and pH from 7.92 to 8.33. Marine velvet/white-spot-like symptoms, body haemorrhage and mouth fungal lesions were observed during the study. Correlation analysis indicated that bacterial disease showed a negative relationship with temperature (r = −0.676) and pH (r = −0.652), but a positive relationship with salinity (r = 0.602). Protozoan disease showed moderate positive associations with salinity (r = 0.461) and pH (r = 0.322), whereas fungal disease showed relatively weak correlations with the measured environmental parameters. The findings demonstrate that variations in water-quality conditions are associated with disease occurrence in captive A. sebae. Continuous monitoring of physicochemical parameters, quarantine, sanitation and early disease detection are therefore essential for maintaining the health and sustainable hatchery production of this valuable marine ornamental fish.