After many attempts at imaging life in pond water, I finally chanced upon a tiny swimming creature. Thanks for all your helpful tips , which really came in handy.

Here’s a video of what I saw:

I was super excited to see this (you can probably hear that in my voice). I posted a quick video on twitter and asked for help identifying what I was looking at, and quickly learned that this was a water flea , possibly a Daphnia . ( Thanks to Shreya Dasgupta , Subhojit Roy , and his 8 year old son Vijay for help identifying it.)

I love the detail that you can make out with the foldscope. You can clearly see the compound eye (reddish center in a black circle), the pouch with eggs in it (wow! So this is a female, and she’s a mom), the tail with what seem to be hairs at the tip (I wonder what their purpose is?), the beating mouth parts, and the antennae beneath the creature.

This creature was a former resident of the Hauz Khas Water Tank in Delhi, a structure with a rich history that traces back to the 13th century, when it was created as a water reservoir for Delhi’s newly built Siri Fort .

Today, the water in the reservoir has an alarmingly bright green color, and is home to many kinds of aquatic birds. I’ve long wondered what’s in the water, and the foldscope gave me an opportunity to find out first hand. So I collected a jar full of water from the reservoir and put a drop under the foldscope.

This Hauz Khas complex (the reservoir and the adjoining parks and monuments) are a threatened oasis of biodiversity among densely urban surroundings. Here are some pictures of the reservoir to give you a sense of the place. I feel like the half-sunken boats and garish green water lend this place a distinctly post-apocalyptic vibe.

What do you see in the water flea video? Post a comment with your thoughts / observations / ideas.