I was fishing with cut squid on a reef near Koh Kut in the Gulf of Thailand with renowned guide Jean-Francois Helias of Bangkok when I hooked what I presume to be a batfish. Even after looking in various fish-identification books, I'm still not sure which exact species it is. Can you shed any light on this?
San Ramon, California
A: That's a rather large teira batfish (Platax teira), a common inhabitant of the western Indo-Pacific. A number of species of batfish (or spadefishes as they are known in some parts of the world) are found in Thailand, but P. teira can be differentiated from the others by its distinctive dusky-yellow pelvic fins and a dark blotch just above the vent near the anterior margin of the anal fin.
Juvenile teira batfish inhabit protected inner reefs; they're striking fish with very long, flowing dorsal, anal and pectoral fins. Because of their elaborate fins, the juveniles aren't very strong swimmers, but they get by through the use of camouflage and by imitating floating leaves and other debris. These batfish can grow up to about 19 inches. Adults occur near structure - mainly reef edges, but also wharves and jetties. Their diet consists primarily of small invertebrates (crabs, shrimp, mollusks), while juveniles eat mainly plankton.
- Ben Diggles