Nitrate was at 20 mg/l which is about the same as in the tap water I am using. That means that the umbrella papyrus ad not yet started to significantly consume nitrogen. As the nitrite levels were below detection limit, I decided to add the first fishes: 6 a-few-days-old Heterandria formosa, born in my 25 litre tank. I figured they might welcome the copepods as a snack and at the same time wouldn't adversely affect the water quality too much.
A group of adult male Heterandria formosa. |