When I was in my adolescenthood , I always wondered how these fishes appears by their own in stalled waters. Science gives us an opportunity to question. Why? Where? & How? Those fishes that used to appear in logged waters are actually Gambusia, the mosquito eaters. Over the years these Gambusia fishes serving as natural cleaners, feeding on larvae of mosquitoes. Yes, the mosquitoes! Being Delhite I think i don't have to tell what mosquitoes can do. As we see increasing cases of Dengue and Chikungunya in past few years, now I know what had changed in these years. The population of frogs and Gambusia came down and there is drastic increase in mosquito population.
Other natural cleaner of environment which eats up the mosquitoes are frogs. How often you see frogs hopping in rainy seasons? Being an Amphibian species frogs are biological indicators of any changes in climate. They respond to alterations in moisture and temperature.
Their thin permeable skin cannot adapt to the changes in aquatic and terrestrial environment. With no frog around we can think where we are heading towards. The increased cases of Dengue, Chikungunya and many mosquito bite disease are the result of over interference of human in ecology. Global warming is on the rise. Food chain is disturbed already. We can see alteration in weather phenomena. We are struggling with antibiotic resistance. And what not? The situation is bad today but it may go worst if we do not take appropriate actions.