And yes, I keep them several in each tanks also mixed with each other, they do fight sometimes but with enough space sub dominate recuperate fast and saga continues.
Red Tail is always winning and seems stronger more powerful fish.
Some of my sharks live with large CA/SA cichlids (over 10") and I never accounted any (sharks) missing, guess they are not as tasty as Chalseus or Gouramis (except Kissers) who all become a snack.
Both of these sharks are great scavengers, better then any cory cats I had, also being much more colorful...
