Acridine orange is a fluorescent dye that can be excited with blue-cyan light and upon binding do DNA and RNA it fluoresces in green and red respectively (there are of course other things that make it glow green or red). Here I added the tiniest drop (< 100 nanoliters) of an acridine orange stock solution to a drop of pond water and captured a few images I decided to share. All images were acquired with the following fluorescent setup: 450-490 bandpass excitation filter, 510 dichroic mirror and 515 longpass filter.
![Image](https://kopame.com/dmqk/dmqm/media/paramecium_AO.jpg)
A paramecium I think. Plan 16/0.32
![Image](https://kopame.com/dmqk/dmqm/media/merismopedia.jpg)
Merismopedia. Neofluar 40/0.75
![Image](https://kopame.com/dmqk/dmqm/media/3763_AO_40.jpg)
Colonial algae. Neofluar 40/0.75