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Yellow boxfish

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Our oceans are full of splendid creatures, many of which remain to be found. Today, I want to introduce you to what is possibly the cutest aquatic animal, the yellow boxfish.

As suggested by its common name, the yellow boxfish (Ostracion cubicus) is a yellow and... box-shaped fish. Also known as Polka Dot Boxfish or just Cube Boxfish, this astonishingly cute creature has a world wide distribution, occurring in coral and rocky reefs of all three major oceans, at depths ranging from 1 to 280 m (3-920 feet).

Interestingly, the bright yellow coloring of the species is actually a warning to any predators out-there that the animal is poisonous and possibly deadly if consumed. When in danger or under stress, they excrete poisonous proteins from their skin that affect all fish swimming in the surrounding waters.

Let's find out more about these magnificent little critters!

Gimme a kiss!

Gimme a kiss!


Juveniles are easily identifiable by their yellow box-shaped body, covered with brown or black spots. However, with the passing of time, these strange sea animals become less and less cute.

The body becomes more elongated, the number of spots decreases and the yellow coloration fades to a dirty, mustard-like color. Adults old enough to reach the length of 45 cm (about 18 inches) usually have a blue metallic coloration.

Here's a video showing this beautiful creature in action:

Behavior and Reproduction

There's not much research on the species and as a result we know little about their behavioral and reproductive patterns. They are slow swimmers, spending most of the day on or near the same spot.

They live a solitary life, swimming in oral and rocky reefs, in depths ranging from 1 to 40 meters. Males appear to be territorial, especially during the breeding period -in Spring- when they form harems, each consisting of one male and 2 to 4 females.

Adult yellow boxfish-Notice the mustard-like color

Adult yellow boxfish-Notice the mustard-like color

What do they eat?

The yellow boxfish primarily feeds on algae, though it may have an occasional snack from any of the below:

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  • Crustaceans
  • Mollusks
  • Polychaetes
  • Small fish
  • Sponges
  • Worms

Juvenile yellow boxfish

Juvenile yellow boxfish

Are they suitable for pets?

First, I want to say that I am against holding any kind of non-domesticated animal as pet. But even if you don't agree with me, you probably won't have much luck with this animal.

As of today, even expert aquarists have had very little success keeping them alive for long periods of time. Apparently, the species has many special requirements. Furthermore, experts say that even under minor stress or discomfort, the fish releases a poisonous substance (called ostracitoxin), which has the potential to wipe out all life in the tank!

Conservation Status

The species has a worldwide distribution and no common natural predators, thanks to its poisonous nature. Furthermore, its not commercially fished and there is little demand for it in the pet trade.

Its conservation status is still to be officially assessed, however, considering the above we can safely say that the yellowbox fish is not under immediate threat.

Maybe factors like pollution and global warming - both of which affect all life in Earth - may one day pose a serious danger. For now, the species appears to have a bright future :)

Similar Species

The yellow boxfish is sometimes confused with the Longhorn Cowfish (Lactoria cornutawhich), a closely related and similar looking fish that comes by the same common name. The Longhorn Cowfish is easily distinguished by its long horns, as you can see in the videos below:

Yellow box fish and Longhorn cowfish

More strange and cute aanimals

I really hope you enjoyed reading about this cute sea animal. If yes, please consider liking, sharing and possibly subscribing to me, as there are more to come!

In the meantime, you may also want to check some more strange animals:


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