I bought myself i pair of gold rams 2 and a hlf weeks ago,they seem fine and look fine but ive caught 1 of them flicking and rubbing itself ,not all the time but just now and again,ive done an ammonia test and my tank which is 9 month old has zero ammonia,i also do 20% water change weekly and clean gravel weekly too,i know these fish are sensitive,but i thought id had everything covered,is there anything im missing!.