The other day I noticed my Otocinclus had a small whitish, puffy spot on his side. I think it is a fungus (columnaris). Pictures (sorry for the quality--I only have my cell phone to take pictures): Earlier tonight, I set up a 3g with heater, filter, air stone and no gravel to put him in tomorrow (waiting for heater to get the temp. up). I put a used cartridge from my 6g in the filter and filled it with 2g of water from the Otto's aquarium and 1g of new water treated with conditioner and Garlic Guard. I also bought Maracyn by Mardel to treat him with. I've never used this before; would it be ok to put a whole packet into the 3g? The instructions don't say. I'd really appreciate your help!!!