Fungus on uneaten food

[ikan]

Lately I notice that uneaten food are covered by fungus the following day. I feed my plecos at night mostly Hikari sinking Pellets and now whatever left is covered by fungus. Didn't have this problem before. I tried a couple of doses of Melafix but it doesn't help with the fungus. Nothing has changed in the tank with water change routine, temp etc in the last 2 years. My other tank was attacked by fungus and I just clean the whole tank to start again because I lost most of the fish.
I know I need to do water changes perhaps daily until the problem go away. But I will need a medication to remove the fungus. What should I use. The fish don't seem to be sick but I want to remove the fungus.

[Silurus]

I think if you remove the uneaten food, the fungus will go away.
Since fungal spores will always be present in the water, it's impossible to have uneaten food in the tank and not have fungus on it.

[polkadot]

Go easy with the feeding, dont feed more than what they can eat one night.