Efficacy of Probiotics in Improving Water Quality and Bacterial Flora in Fish Ponds

Fish culture aimed at high production through intense culture practices often leads not only to the
alteration in water quality but also to severe disease problems. The accumulation of organic wastes
deteriorates water quality and encourages the proliferation of pathogenic microorganisms. To avoid
these problems, probiotics are used as bioremediation tool. The present study was aimed to know the
changing patterns of beneficial and pathogenic bacterial loads and water quality in fish ponds treated
with pond probiotics. For this study, three earthen fish ponds, were cultured Pangasius sutchi, Catla
catla and Labeo rohita, located in Balliparru near Machilipatnam in Krishna District, Andhra Pradesh,
India were selected and studied for a culture period during 2009 to 2010. Two ponds were treated
with probiotics having Nitrosomonas (1.62 kg/ha) and Nitrobacter (0.82 kg/ha) species and one pond
was kept as control. During the culture period (August 2009 to July 2010), water quality parameters
and the populations of total heterotrophic bacteria (THB), beneficial bacteria (Nitrosomonas and
Nitrobacter species) and pathogenic bacteria (Pseudomonas) in water were analyzed. It was
observed that in treated ponds, THB and beneficial bacterial load increased and pathogenic
Pseudomonas load decreased. The bacterial population changed during every fortnight sampling of
the culture period. The changing patterns of different bacteria in treated and control ponds were
compared and discussed. The concentrations of ammonia, nitrite and phosphates were observed to
be low in treated ponds than in the control pond. The present study revealed that the probiotics are
instrumental in maintaining good water quality, higher beneficial and lower pathogenic bacterial loads
in fish ponds.