shnider skink

Question
hi i have two skinks in a 30 gallon long their doing fine but i also have a fence
lizard in there with them does anyone know if this is safe ? will they fight?

and is there any visible sexual difference to check if its male or female besides
the head being wider?

Answer
 A 30 gallon is great for the two skinks.  But I am always opposed to mixing species, especially when they come from two different continents.  Schneider's skinks are African, they need a fairly dry climate, where fence lizards are more forest animals.  I would give the fence lizard his own habitat and really concentrate on giving each species as close to a natural environment as possible.
 Since there are several kinds of fence lizards and a few kinds of Schneider's skinks, I suggest you look at anapsid.org and look up which ones you have and go by Melissa Kaplan's advice for each.
 Sexing of skinks also can depend on the specific species and family group.  Males sometimes have thicker necks, some have hemipenal bulges, and there are some species, where you have no clue till one lays eggs or a DNA test is done.