I notice that my water bottle baffle had mold in it so I took that apart and then notice it was coming from the filter. I have not seen it on the fish nor any where else in the tank. So I shut the filter off and I cleaned the fungus/mold off. I noticed it did have a little stench to it but nothing that was terrible that I couldn't stand. It was more mushy than anything. I don't wanna replace the cartridge since the beneficial bacteria. What could the fungus/mold be a sign off? The tank is about 2 months old. I cycled it for a month. I did have a problem of foggy water. Other than that the parameters of the water are all where it should be the water is crystal clear, I do 50% water changes weekly and a 10% water change mid week. It is a ten gallon with a divider.
Here is a photo I found on google. It looks very similar just what I found in my tank was more dark like a gray color.