Today’s fish is a peculiar looking soul with a beautiful juvenile stage that often sneaks into photos taken in the eastern Pacific.
The Mexican Hogfish, also known as the Streamer Hogfish or the Vieja Mexicana, are members of the Labridae family. This is one of the largest family of fish also referred to as the Wrasse which includes over 600 species. The best way to tell a wrasse from other fish is they tend to swim using their pectoral fins rather than their tail fins in a breast stroke motion. For a little extra fact, the word wrasse comes from the old Cornish word wragh, meaning old woman or hag!
What’s in a name?
The Mexican Hogfish gets its name from its range, primarily being west coast Mexico and the eastern Pacific. The other name, the Streamer Hogfish, is where the scientific name is formed. The first word ‘Bodianus’ comes from the Portuguese word pudor, meaning modesty. The second word ‘diplotaenia’ comes from two Greek words, diploos meaning twofold and tainia meaning ribbon. This refers to the two dark stripes that can be seen on the sides of the juveniles.
Habitat and distribution.
Mexican Hogfish can be found all along the west coast of the Americas, from Baja California down to Chile. They are most often spotted in the Galapagos, Socorro and Cocos islands. Sticking to reefs and seamounts, they can be found down to a depth of 75m but are more regularly seen in 10-18m region. They can also be found in areas with sandy bottoms or places with abundant marine plants. Mexican Hogfish are usually found alone but can be seen in very small groups, especially during breeding times where they form distinctive pairs. They are another species which broadcast spawn, releasing eggs and sperm into the water column to drift away.
Looks that kill.
This fish is another that goes through a couple of changes throughout its life. It has 3 phases: Juvenile, Initial and Terminal.
The juvenile phase is the youngest and at this point they are all female. It is often seen as dappled red to pink along its body fading into a bright yellow tail. If you can get close enough you can see a darker red outline on its scales. It also has 2 dark brown to black stripes that go along its length both joining at the eye. These are the ribbons that give it its name. At birth however it is a solid yellow with a bright red nose.
As it matures into the initial phase the red starts to take over the body. The front teeth of the fish will also start to become larger and more defined as their diet changes. This give the fish a goofy or sinister look, depending on your point of view! Adding to the goofy look, they start to grow a large lump on their heads. It is unclear as to what the function of this, possibly it helps with feeding or as a mating ritual like the Bumphead Parrotfish does. Maybe it is just a sign to show how dominant a male it is. The fish also starts growing a yellow streak on their flank which continues to grow as the fish ages.
Finally, the fish enters the terminal phase. At this point the fin rays start to extend and the fish takes on a blue to green hue. The oldest specimens have very little red left on them and have a pale white lower jaw. When they enter this phase they also change into a functional male.
As I mentioned earlier, all Mexican Hogfish are born female and change into males as they age. This is called sequential hermaphroditism, which is where an animal changes from one sex to another. We have touched on this in a previous Findex but with these fish it is a little different. They will almost always change into a male with age however they can delay this change to fit with local conditions, for example if there are already lots of males around. No one is really sure why these fish choose to do it this way round, as a sensible idea would be to be a female when you are larger because eggs are larger and require more energy to make than sperm. One possible reason why is to maximise egg production while young as these fish don’t often live in groups for protection.
Mexican Hogfish regularly grow to around 35cm in length but have been seen as large as 75cm and weighing around 9kg.
Life on the reef.
Mexican Hogfish are a reef fish, so don’t expect to see them out in the blue water. As it can be found along the Pacific East Coast there have been local differences based on where you are. In most places it can be found in all habitats, even up estuaries, except in the Gulf of Chiriquí, where it won’t go over sandy areas or broken rubble.
Using its strong teeth and jaws it preys upon crabs, brittle stars, sea urchins and molluscs. It is unknown if it uses the bump on its head to break into coral to get to prey.
During the breeding season the male Hogfish will patrol a territory called a lek. The females will then enter his lek and they will pair off to breed before he returns to go again. Having a good lek is important as bad locations will lead to less female interest. They may use their head bumps to defend or fight over mates or lek ownership but this hasn’t been documented, so there is a project for our budding scientists!
These guys tended to keep themselves to themselves but often would follow our lights to see if there was any food highlighted in them. Older individuals would cruise along with us as if to keep an eye on what we were doing. At night we could see tem sleeping inside a mucus bubble, which hides their biological signals from things like sharks and other predators. There are plenty of cool ways to photograph these guys as well. Do you get them from the side and show off the colours and patterns? Or do you shoot from the front and capture a dorky smile with their head lumps and big teeth?
The bottom line.
We travelled on the Humbolt Explorer in the Galapagos to see these fish. In the Galapagos you are spoilt for beautiful life all around you so I can’t blame you for not noticing these. However, they are a beautiful to look at and their goofy smile always makes me laugh. Seeing them in all their stages is a real treat and make a great photo collection project.