The Magical Colour of Fish
The world under the sea is sometimes unimaginable
and Magical at the same time as we know it. Wander around the stunning Apo reef in the
South China Sea on the Mindoro straits, Philippines, feasting your eyes on the colourful and vibrant
colours in the Rainbow Reef, Fiji and strolling around the pristine water of
the Great Chagos Archipelago, enjoying the diversity of coral reef and fish species. You might get the thrill of seeing such a
colourful and magnificent colour of reef fish. But, what makes them so special to be given
those breathtaking looks? Well, the diverse and brightly colour of reef
fishes does not evolve for the human eyes to feast. As a matter of fact, those bright blue neon
damselfish and that striking orange stripes on clownfish are there for their survival.
Basically, the most fundamental factors in animal survival are three things.
The ability to eat, not be eaten and the chances to reproduce.
These three factors are important in order to ensure their species survival.
And colours are correlated with the second and third factors. In order to not be eaten, they can either
camouflage to match the background colour or mimic other species. A study by Justin Marshall in 1998 in Great
Barrier Reef, has documented the effectiveness of grouping in certain reef
species It is called disruptive camouflage. For example, When you see a group of zebra,
similar like bold coloured reef fish, group together for protection,
the predators might not see an individual zebra or a fish,
but rather a school or herd or might be a typical natural background when viewing against
the highly pattern background of the animal habitat. In fact, there are certain species who could
transform colour naturally according to the background like a chameleon.
Triggerfish and goatfish are the best examples. When talking about avoiding predators, some
species might have a brightly coloured body to fool their predators. And some even having this speciality to be
a predator. This type of species is actually poisonous
and dangerous and there is a term for this, which is called aposematism or warning colouration. Fish with aposematism may use this special
ability under two conditions, one, for aggressive mimicry meaning to imitate
one or more traits from other organisms to harm them,
such as this bluestrip fangblenny (Plagiotremus rhinorhynchos) who mimic the Bluestreak cleaner
wrasse, who is a cleaner fish. The fangblenny, on the other hand, use their
mimicry ability to get close to other fish and feed on their tissue. Another type is defensive mimicry
like the spotted mandarin fish who use their brightly coloured skin to alert other fish
about their danger and avoid predators. Ok, so what about using colours for mating
purpose. Reef fish know that they have different patterns
between each other either from different species or within the same species. Each and every one of them is different. Hence, colour enables them to differentiate
each individual and for that reason, mating. Some species present different colours between
male and female, which is called dimorphic species. This types of species use colours as a sexual
signal either to attract or intimidate others. and this is what makes colours of reef fish
unique and important at the same time. What do you think of the colour diversity
in reef fish? Share your thought in the comment section
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