Hi guys, I am new at this. I have a peacock eel had him since 3/2015.He was always active and eating happily. However, for the past 3 weeks he has been in his favorite spot (under the sand) , he will not even come out to eat. He shares the tank with 2 gouramis, a panda cory, a rainbow shark, a bumblebee catfish, 4 coolie loaches and a albino algae eater. My water quality is good as is the temp. Is this normal for them to go into hiding for weeks. I have done my "home work" on my fishes long before I purchase. All seems normal so what is the problem, I am very concerned as it is my favorite fish in my tank. Thanks ANYONE,,,, Help!