I have a 65 gal tank with 4 sals, 2 bellycrawler pikes, a galaxy pleco and 5 giant danios.
Two of the sals have paired up (One of the others is a female, not sure on the sex of the 4th one...sometimes looks very female, other times very male) and spawn every week or two. They have yet to actually raise a brood, but they sure try.
Even with the pair doing their thing regularly the tank is very peaceful. The breeding pair will chase the other two sals if they get too close to the breeding area, but no damage. My female bellycrawler pike rules that tank...she goes where she wants, when she wants. Again, though, no bloodshed. Fights between the sals and the pikes consist of flaring and open mouth displays.
Nobody pays any attention whatsoever to the danios or the pleco.