yeah, its black moon sand mixed with a little grey and white gravel, there are 5 in there and i went to put a small java fern in the tank and i was attacked by the largest one. Kinda humerous but im wondering if this is a normal sign of territorial aggression or if they may be breeding in there already? i've noticed the largest occie displaying to a couple of others but their has not been hardly any aggression amongst each other.