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Introducing the Boxfishes, Trunkfishes, and Cowfishes

Hello, Frank Indiviglio here.  With rigid bodies propelled “helicopter fashion” by tiny fins, the 33 marine species that comprise the Family Ostraciidae are quite amusing as they motor about.  Their appeal is heightened by an “alert” face and, in many, horn-like projections at the head and rear.  Some species grow quite large and require unique diets, but several make interesting, appealing aquarium subjects.

A hard bony carapace protects cowfish relatives from attack by many predators.  However, all are slow moving, and their rapidly undulating fins seem to draw attacks from smaller fish.  Oddly enough, the skin over their rigid protective plates is quite sensitive.  Be sure to watch your specimens closely, lest wounds inflicted by tiny fishes go un-noticed and lead to infection or stress-related diseases.

A 40+ Year Old Memory of a Long Horn Cowfish, Lactoria cornuta

A brilliant yellow body highlighted with blue spots and set off by “horns” at the head and rear renders this droll fish instantly recognizable.  I have a soft spot for these comical fellows.  Back in the early 1960’s, when my grandfather lured me into keeping marine fishes, a long horn cowfish was my first exotic species.  Armed with pioneering marine aquarist Robert Straughan’s 1959 classic The Salt Water Aquarium in the Home, we frequented the 2 NYC aquarium stores (1 in the Bronx, 1 in lower Manhattan) that stocked marine fishes.  Shipments were irregular at the time, but we lucked out on 1 trip with a gorgeous cowfish. 

All-glass tanks were not yet available, so we installed our prize in a large plastic aquarium, where he impressed me greatly by being the only one of  my early purchases to survive my clumsy attempts at marine fish husbandry! 

Slow feeding and peaceful (although aggressive towards other cowfishes), the long horn is one of the few fishes that I was able to house with another long-time favorite, the Atlantic seahorse. 

Hovercraft Boxfish, Tetrosomus gibbosus

This species’ mode of swimming truly fits its name, with only the fins fluttering, propeller-like, as the rigid body moves along.  They are extremely inquisitive, seeming to notice and examine all happenings within and outside of their aquarium.

Maturing at a mere 4 inches in length, hovercrafts are an excellent choice for those lacking space to house long horn cowfishes and other large species.  They are, however, slow to feed, and so their condition should be monitored closely…the stomach areas of underfed boxfishes will rapidly take on a sunken appearance.  However, when housed with other small, methodical feeders (seahorses and pipefishes are worth a try), hovercrafts do quite well.

Husbandry Considerations

Many cowfish relatives are, despite their “apparent calmness”, quite excitable.  Frightened specimens will release a skin-generated poison into the water.  Known as ostracitoxin, this secretion is toxic to other fishes, and, in close quarters, to the toxin-producer itself. 

Establishing cowfishes in an aquarium before adding other species, and choosing only slow-moving, peaceful tank-mates, will go a long way in preventing disasters.  In a dark room, always turn a small room light on before using the aquarium canopy light.

In the wild, cow, box and trunkfishes feed largely upon algae and sessile invertebrates (i.e. sponges, tube worms).  Captives take a wide variety of frozen, freeze-dried  and algae-based foods, along with live brine shrimp, mysids and blackworms.

Further Reading

For further information on the long horn cowfish, please see Species Profile: the Long Horn Cowfish.

Please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

Image referenced from Wikipedia and originally posted by LASZLO ILYES

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.