Very little is known about the behavior in this species. They have been observed preening high in the forest canopy. When foraging, they will call continuously tz or tze often repeated in succession (Restall et al. 2006).

There is no information on territoriality in this species.

Nothing is known about sexual behavior in this species. Adults have been observed feeding young (Solano-Ugalde et al. 2007, Múnera 2014).

The Scarlet-breasted Dacnis is usually seen in pairs, but also often associate with mixed-species foraging flocks (Ridgely and Greenfield 2001). They have been observed in small family groups, and were observed with other insectivorous birds aerially consuming insects attracted to flowers (Múnera 2014).

Predation on this species has not been reported.