1.Ostracion is commonly known as coffer-fish or trunk-fish.
2.The body is short, roughly triangular and variedly coloured. Body is divided into head, trunk, and tail.
3.Body is covered in a carapace formed of large juxtaposed hexagonal bony plates. Each bony plate has blue spot in the centre. Carapace is closed behind the anal fin.
4.The contour of the body is three ridged, the median ridge is elevated into a sharp dorsal spine which is triangular in shape.
5.A compressed supra- orbital spine above the orbit is directed upwards or a little backwards.
6.Dorsal and anal fins without spine. Caudal fin is round and acts as rubber for swimming. Pectoral fins are large and help to form water current. Pelvic fins are entirely absent.
7.Ventral side has backwardly directed spines.
8.Gills are four in number, gill-slit is situated near the pectoral fin.
9.Exhibits warning colours and acts as danger signal to predaceous fishes. Some trunk fishes discharge a toxic substance ostracitoxin that kills other fish in confined water. It is also toxic to trunk fish itself.
10.Ostracion is widely distributed in Red sea, Indian seas to the Malaya Archipelago, African seas, Atlantic and Pacific Ocean.
Source:
1. Practical Zoology Vertebrates by S.S.Lal. 2. A Manual of Practical Zoology Chordates by Dr. P.S. Verma.
