Trigger-Fish and Angler-Fish

Finally we have the order Tetraodontiformes containing the family Balistidae which features the trigger-fish, and the order Lophiiformes containing the family Lophiidae of which the angler-fish is a member.

The former order contains some remarkable fish with inflatable prickle-covered bellies, but these do not concern us here. The trigger-fish, which does, occurs in North American waters (where it is known as the grey trigger-fish) along with many close relations, and is occasionally taken in British waters. ‘The name trigger-fish and indeed its generic name Balistes are given to these fish because of the curious structure of the spiny dorsal fin. The large first dorsal spine, when erected, locks into position and cannot be lowered manually. The small third spine, however, acts as a trigger, and when this is depressed the locking apparatus on the first spine base is released and the fin folds down.’ (Wheeler.)