Hey guys I'm new to the hobby, with only a less than a year experience. Right now I have a 20 gallon tank with 2 two inch sun catfish, 1 three inch channel catfish, 1 three inch synodontis multipunctatus (or maybe a hybrid synodontis, thats what the tag said at the store but i think otherwise), and 2 less than an inch albino cory catfish. They all live happily together under the driftwood and frequently come out and play even during the day. Just switched to sand from gravel and got the water crystal clear. It was a hard choice but the end results were fantastic when my fish were alot happier. I am aware of my fish' adult sizes and overstocking. I am in the process of setting up a way bigger upgrade in their stages of evolution. My ph balance is at 7, and I keep the temperature at 78ºF. And I dechlorinate the water with Prime and use stability. The problem I seem to be having is a parasite? Two weeks ago my channel catfish started scratching against the sand. I checked for ich thoroughly throughout the next few days. There was nothing, so I went to my LFS and asked the guy, and he claims its just a normal behavior. So I went back home and looked it up and couldnt find anything about it except for diseases and parasites. So I raised the temperature slowly throughout the week to 84ºF. I reduced it back down to 78 again later on the week and added Mardel's Quick Cure, not directly of course. And I've taken out the carbon, then replaced it after 24 hours to absorb the last treatment. So far this is my 2nd day of treatment and I still notice my channel scratching. Rarely I will see one of my sun catfish doing it too. I am beginning to worry now, because I am running out of options. I've had ich problems before and i've treated and got rid of them easily. But this doesn't look like ich, theres none anywhere. Its got to be something, unless they just have an itch too sometimes. Or maybe its the sand? I used aqua terra sand, rinsed it as best as I could. I don't know, any advice is very much appreciated and thank you for taking your time to assist. I want my fish to live in peace. Not rest in peace.