Honeycomb Cowfish

A guest speaker came to class to discuss coral reef fish. After lecture the class picked their own specific fish to write a blog. Today I picked Honeycomb Cowfish due to its unique phenotype of hexagonal scales and uncommon body shape. 

The Honeycomb Cowfish scientifically is referred to as Acanthostracion polygonius [1]. This name refers to genus and species respectively. It belongs to Ostaciidae family, typically known as boxfishes. Most boxfishes release poison when stressed however I didn’t find any information about induced poisons in Honeycomb Cowfish. The structure of fish in the family include many bones and are shaped like a square. They have small mouths and broom like tails that help with swimming because the boxy shape weighs them down. Honeycomb Cowfish however are a rare species and have heavy hexagonal scales that cover the whole body. Another form of defense are tiny horns that protrude over the eyes.  They typically grow between the range of 7 to 15 inches and are commonly found in water depth of 20-60 ft, meaning they inhabitant the neritic zone [2]. The habitat is in the western Atlantic Ocean, found as far up on the coast as New Jersey and as far as southern Brazil. Found typically in the Caribbean and Gulf of Mexico. They choose to reside in clear water of coral reef habitats and in close vicinity. The average temperature water is 22-27 degrees Celsius and are considered diurnal [3]. 

A closer look at the biology of the fish shows the hexagonal scales are attached firmly to each other except around the head and tail of the fish. This allows for respiration and movement for the gills, fins, and eyes, and caudal peduncle [2]. The color of the fish is also a unique characteristic, they are seen in blues and greens and yellows and brown. The dorsal edge is seen to have darker and/or irregular hexagons due to opening of the scales [2]. Juvenile fish are more brightly colored and have shorter dorsal fins. The honeycomb scales are used for protection [3]. The Honeycomb fish feeds on marine invertebrates mainly shrimp, tunicates, and sponges. The structure of the small mouth is used to suck in the small food particles. Their food source is mainly sessile making it easy to find, not much of hunters. This is due to their nature of solitary and are never seen in a group more than 3. Typically, when grouping, the small school will compromise one male and two females [3]. Not much is known about the reproductive nature, but many scientists conclude this may be significant. It is known they are open water mating fish. Meaning they swim to the surface quickly release gametes and swim back down immediately. 

Like many fish they undergo different life stages. For Honeycomb Cowfish they have two stages of juvenile and adult. Juveniles are rounder and brighter in color. They can also change color to protect themselves from predators [3]. They do this by sending a signal via nerve impulse to Chromatophores, which are pigment cells in the scales. To learn more about this process watch this video [5].

Predators of these fish are larger fish but usually they are undesirable due to their external armor. As the fish grows into adulthood their colors fade, they also become more triangular and rigid resulting in awkward swimming. A way to protect themselves is to use camouflage by blending into the colorful surrounding of coral reefs. When stressed adults can brighten their colors to be more effective. When using camouflage, they remain stationary for long periods of time. 

Overall, Honeycomb Fish are very unusual fish and use honeycomb shaped scales as protective armor. They can also use their bright colors to blend into coral reefs to hide from predators and the boxy shape makes them undesirable to natural predators. Unfortunately, I noticed this fish is used a lot for commercial use and pet which can damper population sizes. By choosing their habitat close to coral reefs they have easy access to their food source as well as shelter. These fish are really interesting. If you want to learn more about boxfishes here watch this video [4]. 

Works Cited

[1] Charpin, F. (n.d.). Caribbean Reefs. Retrieved from https://reefguide.org/carib/honeycomb.html

[2] Acanthostracion polygonius. (2018, April 30). Retrieved from https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/acanthostracion-polygonius/

[3] Bisson, A. (2015). Ancanthostracion polygonius. Retrieved from https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/images/Acanthostracion%20polygonius-%20Honeycomb%20Cowfish.pdf

[4] SZtv, W. U. (2011, May 12). Boxfish vs. Scorpionfish. Retrieved from https://www.youtube.com/watch?v=o4J8tHaaACQ

[5] How do chameleons and other creatures change colour? (n.d.). Retrieved from https://phys.org/news/2013-05-chameleons-creatures-colour.html