there's some oil-like substance floating on top of my betta's tank. It is a 2.5G tank and just recently i noticed it when i checked the tank against the light. Is it waste? i want to know what it is! I did water changes to remove the stuff but it keeps on coming back. How do i get rid of it? thanks!
What are your water parameters? when cycling my tanks I noticed this as well and it seems to be a build up of amonia, nitrite, nitrate. Water changes would help in that case, but as mine was a fishless cycle I just let it run it's course.