Weird Black Substance In Tank?

  1. k

    kalexis1800 Member Member

    So I have my Betta in a 5 gallon tank with black sand, a green plant ball, and a decor skull. I noticed there's a black substance in the tank, and was curious on what exactly it is and how to prevent it again? 7d9430ccd2208047ae6046cd6ebe3f29.jpg
  2. goplecos

    goplecos Well Known Member Member

    You really need a better pic, but I think it's black algae. It's not harmful because you only have a moss ball, but it's super hard to remove. You have to scrub it really really hard.