Why Are They Called "Trigger" Fish?
As you can see in the above photo, Triggerfish have a top dorsal spike that can be put into an up
down position by the fish. At the bottom of the body, where it
widens out, there is another smaller, permanently extended type trigger
that can be flexed too. When this fish wants to hide it will go into a
hole, stick up its top trigger and flex its bottom trigger, which locks
them both into place. The force of the top trigger in conjunction with
the smaller trigger on the bottom wedges the fish into the hole. Once a
Triggerfish has "trigged in", it is next to impossible to remove
them from their hiding place. This is a trait triggers have for protection.
World wide Triggerfish are
collectively referred to has hu-mu hu-mu's, but in Hawai'i the difference
that sets the species apart is in the ending of the name after hu-mu hu-mu.
For example, the Hawaiian
Black Trigger (Melichthys niger, not to be confused with the
indicus or Odonus
niger) is a hu-mu hu-mu 'e-le-'e-le, the Pinktail
Trigger (Melichthys vidua) is a hu-mu hu-mu hi-'u-ko-le
or hu-mu hu-mu u-li, and the Gray
Trigger (Sufflamen bursa - pictured above) is a hu-mu hu-mu
le-i or hu-mu hu-mu le-i. The rough Hawaiian translation
of this particular fish's name is, "fish with a lei
on its chest".
Now for some reason the Rectangular or Reef (Rhinecanthus rectangulus), the official Hawaiian State fish, and the Picasso or Lagoon (Rhinecanthus aculeatus) Triggers both have the famous Hawaiian name hu-mu hu-mu nu-ku nu-ku a pu-a-'a. Our guess why they are both referred to by this name is because they look so much alike as far as body design, but just have difference colorations and markings. The name hu-mu hu-mu nu-ku nu-ku a pu-a-'a roughly translates into, "fish with a pig-nosed face." This is a very fitting name, not only because the face structure of these fish resembles that of a pigs snout, but also due to a grunting noise that these two species as well as most all triggerfish make that sounds much like that of a pig grunting. Both of these species are commonly referred to in fish stores as Picasso Triggers, but the Rhinecanthus aculeatus is the "true" Picasso Trigger.
The Picasso Triggerfish common name senario is just one example of how confusing identifiying these fish can be. Triggers are found in tropical waters world wide, and the name one geographic location gives them is not always the same as another location. Here are a few more examples: The Rectangular Trigger is also referred to as a Reef, Painted, Black Wedgetail, and "Pig Nosed" Trigger. (Remember the Hawaiian name?) The Gray Trigger is referred to as a Bursa, Lei, Green & White, Scimitar, Scythe, and in Austrailia a Pallid Trigger. The Blackbelly (Rhinecanthus verrucosus) is not found in Hawaiian waters, but this fish is referred to as a Bursa Trigger as well.
As you can see, knowing the fish's latin or scientific name is important when it comes to referring to any Triggerfish or Hu-mu Hu-mu. If you don't it is very confusing to figure out which one you are talking about when dicussing it with other hobbyists, and you may not know which one you are actually buying. If you have been in the saltwater hobby for any length of time you have probably found that this point pertains to ANY fish, invert or coral you have seen for sale in fish stores.
A few other Triggerfishes
found in Hawai'i, but ones that are rarely seen because they live in deeper
waters on the outer edge of the reef; the Spotted (Canthidermis maculatus),
Brown (Balistes fuscus), Bridle-Marked (sufflamen capistratus),
and the beautiful Crosshatch
Triggerfish (Xanthichthys mento).