They are tamtam. I've just checked.
My tank is 180 litres, got live plants, caves and driftwood.
I have 6 diamond tetras, 10 zebra danios, 6 Celebes rainbows, one bristle nose, 5 cories, 3 dwarf honey gouramis and the Betta. All seem fine so far but I can easily remove the Betta and put him in...