Sunday, January 22, 2012

Sharks in the farm!

We have a 200,000 + liter capacity tank that is used for drip irrigation. Two months into operation, we noticed accumulation of algae on the water surface. Algae forms when water is nutrient rich and in the presence of sunlight. While nutrient rich water is great for irrigation, algae tends to clog the drip filters, pipes and drippers.

Algae accumulation in one of the 4 tanks

A couple of farm workers suggested putting a couple of hundred Catla into the tank and that should take care of the algae problem. So we went fish hunting 30 km north of Madurai and returned with 250 Catlas and 250 'Tiger sharks'.

A Catla casualty enroute to the farm.

'Tiger Sharks'

It has been about 3 weeks since the fish have been in the tank and there is both good and bad news. Bad news is that almost all the Catlas fingerlings have been scooped out by migratory birds that have been visiting our farm (especially the water tank) for a sumptuous meal. Catlas tend to swim on the water surface and are easy prey for birds (nobody told me that!!)
Good news is that the sharks have survived and are thriving well on algae and groundnut cakes. They have earned their take and done a good job cleaning up the tank. Sharks prefer the bottom of the tank  and seldom come up which explains their survival in our tank.

All cleaned up..
Shadenet material was later placed on the center walls of the tanks to prevent bird from scooping additional fish, but it was too late for several Catlas..


  1. interesting and informative.
    since u have four tanks..
    u can think of fish rearing also the fish tank water is nutrient rich which when irrigated is good for the growing plants.

    1. Yes, we are planning on starting pisciculture on a small scale in the near future..Stay tuned!

  2. they cleaned up the tank pretty good, I wonder why the municipality does not use these fish in tanks and lakes in and around mumbai...odd as it will atleast get rid of the mosquitoes etc


  3. Very informative ...
    do you have any evaporation control methods in summer?

    1. I am planning to put some thermocol sheets on the surface - an idea suggested by one of our followers - Brijesh..