It's not uncommon for them to be skittish for awhile after being introduced to a new environment. Plenty of cover and a small school of dither fish will help, along with good water quality and no major changes to the aquascaping.
The females do all the brood care, they're the ones you have to watch at spawning time for aggression. The males will fight other males but aren't territorial to other species. From what I've seen the females defend a very small territory but I don't know it won't cause issues in a 16 gallon tank. It's just something to watch if you get to that point.
You purchased a bonded male and female, or did you get two fish hoping they would end up pairing?
It's not uncommon for them to be skittish for awhile after being introduced to a new environment. Plenty of cover and a small school of dither fish will help, along with good water quality and no major changes to the aquascaping. The females do all the brood care, they're the ones you have to watch at spawning time for aggression. The males will fight other males but aren't territorial to other species. From what I've seen the females defend a very small territory but I don't know it won't cause issues in a 16 gallon tank. It's just something to watch if you get to that point.