Review on 5.7lb Black Small Decorative Pebbles - Versatile Gravel River Rock for Succulent Gardens, Home Decor, and Vase Fillers by Chelsea Williams

These are good value for money and the style is nice and definitely easy to clean...but after a few washes they started to ooze some black liquid and detaching, I thought it was from behind the tank was a bit dirty but then I noticed that the tank gets dirty and fogged up too quickly and yesterday my Betta behaved differently, not normal, I felt dizzy when I looked at her again... she was dead :( took when i got her out of the tank i saw a weird discolored part on it like a pink complexion (my betta was all blue beautiful blue) then she started bleeding black something on those pebbles is harmful