5 Gallon office aquarium is not doing so great. 10 new shrimps that I had added seemed to do well for a few weeks, but then one missed week of water change and they are all dead. I think Walstad aquariums are pretty picky on the type of soil that you use. Mine seemed to have a lot of organic matter, the water keeps turning yellow in about 3 days, and is really yellow in a week. I added a pair of Badis Badis which seem to be doing ok, but keeping my fingers crossed. It was a mistake to add shrimp first, since shrimp seem to be much more delicate than the Badis.
I need to change water every weekend otherwise it turns really yellow. Zero maintenance was the main draw of Walstad aquarium in office. I am still hoping that eventually all the soluble chemicals from the soil will leach out that the aquarium will settle down.