only seen them in the wild a foot log ,I wonder where the little ones hang out & eat? Maybe the adults bring some back as they suck up substrate when they think they arent being watched (like ciclids) & change the terrain,though not nearly as diligent as ciclids. sometimes they get pissed if you keep righting the gravel & will whip it with their tails.Best to keep plants above & up behind his hole (cave) or ledge or on oposite side of tank all together if your going to keep him