I have noticed the last few days my guppies are playing in the current from the filter. I thought it was cute, I thought they were being playful, but I just read somewhere that fish that are swimming in the current might be sick. I had a guppy die this afternoon, he was acting funny for the last week, the rest of the fish seem healthy. Should I be worried? Are my guppies playing or are they sick? If this is a sign of illness, what is it and what can I do about it? I had my water tested about a week and a half ago and it was great.