My 55 gallon tank has been up and running for roughly 5 months now and just today I noticed someone digging little pits around some drift wood. Only things I see inhabiting them now are some fry and tiny ghost shrimp, so whoever made them is gone. They're roughly and inch or two in diameter. The things I have in the tank are a handful of guppies, couple of swordtails, one bn pleco, 6 kuhlI loaches, and lots of snails and ghost shrimps. Any idea as to who decided to start digging? Tried to take pics but they're a bit hard to capture. Only thing that I can think of that might have spurred this is my heater was accidentally turned off for two days and I just got it back on yesterday.