Neoniphon sammara, the sammara squirrelfish, also known as the blood-spot squirrelfish, spotfin squirrelfish, armed squirrel-fish or javelin squirrelfish, is a species squirrelfish found in the Indian Ocean and Pacific Ocean from East Africa to the Hawaiian Islands.
This fish has a venomous spine at the corner of its preopercle.
Next to the squirrelfish is the yellow damselfish and the black and white colored half-and-half chromis.
The Threadfin Butterflyfish is a reef-associated fish and its does not migrate. Its depth range is 1-35 meters / 3-115 feet. It can be found in several different types of habitats, including corals reefs, inshore waters and rubble covered bottoms with prolific plant and algae growth.
I have seen and photographed this fish many times in the Red Sea.