Hey guys. Just got home from work and noticed all four rays showing signs of shedding their coat ? don't know if it is that or it is sand mixing with their slime coat and peeling off. never happened before and water is same as normal and temp and same sand for last two years. only thing different is i have added a small motoro about a month back and all been o.k until now. all rays different sizes and ages so don't think it is a coat shedding thing as i would have seen it before ? what do you think it can be ? all rays acting and eating normal.