Can anyone help me identify this brown, broken-open capsule I have recently found on the decoration of my fish tank (20 gal, planted).
All the fish seem fine (4 - female bettas, 10 - leopard danios, 3 - cardinal tetras, 1 - large mystery snail, 3 - amano shrimp, 3 - (small) rams horn snails), but I did recently have some issues with algae/clouding of the water (GH = 80 ppm, KH = 120 ppm, TDS = 756, pH 7.5, NO2 = ~0, NO3 = ~0). This seems to be under control after water changes and cleaning of the substrate.
I have not noticed anything out of the usual in the tank. But this is definitely not part of the original decoration.
Ideas? Is this something to be concerned about?