The Cerulean Flycatcher is recorded in forest in southern Sangihe, Indonesia. It catches insects in the canopy and gleans from foliage. Knowledge rests on a small set of records, including 33 sightings in 1998–1999, so range and population details remain uncertain.
Adults are about 18 cm, with a long tail and long bristles at the base of the bill. The plumage is bright cerulean blue, with gray undertones on the belly, upper wing coverts, and sides of the neck. Few specimens have been measured, so age and sex differences are unsettled.
In southern Sangihe forest it forages actively in the canopy and sub-canopy, catching flying insects and gleaning prey from foliage; it sometimes descends to low vegetation. Pairs and associations with other birds have been recorded, but observations are too few to describe its whole life history.
An extinction-risk assessment has not been added yet.