I did regular maintenance on canister filter on my poly tank. Not the first time and fiter is an old filter. I am seeing an oily surface with vasline like stuff . which I manually skimmed twice . not too sure what it is.
Not from food because I feed massivore and tilapia and its vet eaten in 10 min.
This layer was not there before this maintenance. Just wondering what it is and is it harmfull to fish ?
Not from food because I feed massivore and tilapia and its vet eaten in 10 min.
This layer was not there before this maintenance. Just wondering what it is and is it harmfull to fish ?