Today while I was checking up on the behavior of a pregnant swordtail, I spotted something odd. Movement is what caught my eye, just below the surface of the gravel, a small, thin black worm was squirming about under the paths through the gravel. Now, I didn't get a great look at it, but I did a little research. One of the possible suspects is a planarian, which can be considered in some part, harmless. This specific animal displays the same behavior of living in sand or gravel. However, I'm not absolutely sure, so anybody who's got some experience with these critters is welcome to give me a heads up. Thanx.
