Coral Colouration

Coral Colouration

Usually, people buy corals that look exotic and contain intense colours only to find out that that precious specimen has eventually turned into a dirty brown tan. Most of these people either sell away these specimens or even throw them away. Then, they visit the LFS again and purchase another specimen. Such actions are very damaging to reefs and inhumane.

Some may ask, why does "expert" reefers here are able to have such colourful specimens in their tanks? And usually this aquarist eventually backs out from this hobby as he cannot get the satisfaction he wants.

Basically, there are 4 main components that contribute to nice colours in corals. These are water quality, lighting, nutrition and genetics.

Water Quality

Water quality is top priority in aspect to colouration. After proper cycling of the tank, ammonia and nitrites are of little concern. The main concern here is nitrates. Although nitrates are very much least toxic than the former two chemicals but it is a good fuel for algae. So what has coral colouration got to do with nitrates?

Majority of corals contain zooxathellae, a single celled algae, in their tissues. These special symbiotic algae are the ones that are responsible for coral colouration. These algae are golden brown in colour and corals have a special enzyme that forces the algae to secrete sugars they produce from photosynthesis. So how does these brown algae produce bright colours?

Going into deeper biology, we know that fluorescent proteins are synthesized when the promoter is stimulated or activated. The stimulus we are interested in is UV exposure. Zooxathellae produce coloured pigments that act as photoprotection from harmful ultraviolet rays. Ultraviolet rays also stimulate the fluorescent proteins and make them glow.

Getting back to nitrates, high nitrate concentration will cause a massive algal bloom within the coral. Although zooxathellae produce colours, the high density of these symbiotic algae actually masked the colours produced. This results in the browning of certain corals. So the first step to ultimate coral colouration is to achieve an undetectable nitrate level.

Lighting

We all know that everything we see around us are actually reflections of light into our eyes. Even if you have the most powerful lighting system, your corals may seem bland as the amount of colour that is reflected into your eyes are low. People using 6500k bulbs generally see corals as yellowish with reds more prominent. This is due to the spectrum of the bulb that leans towards the red region of the 7 colours of white light. 10000k bulbs generally give a more uniformed colouration as it is considered a full spectrum bulb. 14000k to 20000k bulbs bring out the blues and purples better.

Therefore, using a powerful and strong light does not necessary mean that corals will show their nice colours. In fact, using too powerful lights will cause an increase in photsynthesis of zooxathellae so much so that the coral itself suffers as well.

Nutrition

A few years back, people think that providing strong lighting for corals and the byproducts of photosynthesis is enough for the coral to survive. Recently, there has been an emphasis on feeding corals to provide more nutrition. Basically, increased feeding and external nutrition for corals have positive results from more intense colouration to faster growth.

With special regards to SPS, it has also been speculated that addition of halogens also results in the coral becoming a solid colouration but long term usage has not been recorded.

For corals with a visible "mouth", it is recommended that the aquarist feed them small shrimps or scallops and for smaller polyped specimens, it is recommended that specialised food such as Golden Pearls be fed.

Genetics

Lastly, the type of colours you want from a coral depends on its genes. If a coral has genes that makes it naturally brown, there is no use trying to colour it up. That's why you see people collecting specimens from all over the world to add special strains of corals to their stocks. Coral farmers are also looking into reproducing the special strains for distribution. Therefore, do not blame anyone when your yuma or stylo does not turn out as nice as other reefer's.

Copywright Dickson Goh 2005

Bro,
Very good info

Regards

LOL,still got copyright somemore.Well done man,BH...

thks for the info!~

Very informative... thanks bro

[crossdiscus]

Originally Posted by blueheaven

Coral Colouration

Usually, people buy corals that look exotic and contain intense colours only to find out that that precious specimen has eventually turned into a dirty brown tan. Most of these people either sell away these specimens or even throw them away. Then, they visit the LFS again and purchase another specimen. Such actions are very damaging to reefs and inhumane.

Some may ask, why does "expert" reefers here are able to have such colourful specimens in their tanks? And usually this aquarist eventually backs out from this hobby as he cannot get the satisfaction he wants.

Basically, there are 4 main components that contribute to nice colours in corals. These are water quality, lighting, nutrition and genetics.

Water Quality

Water quality is top priority in aspect to colouration. After proper cycling of the tank, ammonia and nitrites are of little concern. The main concern here is nitrates. Although nitrates are very much least toxic than the former two chemicals but it is a good fuel for algae. So what has coral colouration got to do with nitrates?

Majority of corals contain zooxathellae, a single celled algae, in their tissues. These special symbiotic algae are the ones that are responsible for coral colouration. These algae are golden brown in colour and corals have a special enzyme that forces the algae to secrete sugars they produce from photosynthesis. So how does these brown algae produce bright colours?

Going into deeper biology, we know that fluorescent proteins are synthesized when the promoter is stimulated or activated. The stimulus we are interested in is UV exposure. Zooxathellae produce coloured pigments that act as photoprotection from harmful ultraviolet rays. Ultraviolet rays also stimulate the fluorescent proteins and make them glow.

Getting back to nitrates, high nitrate concentration will cause a massive algal bloom within the coral. Although zooxathellae produce colours, the high density of these symbiotic algae actually masked the colours produced. This results in the browning of certain corals. So the first step to ultimate coral colouration is to achieve an undetectable nitrate level.

Lighting

We all know that everything we see around us are actually reflections of light into our eyes. Even if you have the most powerful lighting system, your corals may seem bland as the amount of colour that is reflected into your eyes are low. People using 6500k bulbs generally see corals as yellowish with reds more prominent. This is due to the spectrum of the bulb that leans towards the red region of the 7 colours of white light. 10000k bulbs generally give a more uniformed colouration as it is considered a full spectrum bulb. 14000k to 20000k bulbs bring out the blues and purples better.

Therefore, using a powerful and strong light does not necessary mean that corals will show their nice colours. In fact, using too powerful lights will cause an increase in photsynthesis of zooxathellae so much so that the coral itself suffers as well.

Nutrition

A few years back, people think that providing strong lighting for corals and the byproducts of photosynthesis is enough for the coral to survive. Recently, there has been an emphasis on feeding corals to provide more nutrition. Basically, increased feeding and external nutrition for corals have positive results from more intense colouration to faster growth.

With special regards to SPS, it has also been speculated that addition of halogens also results in the coral becoming a solid colouration but long term usage has not been recorded.

For corals with a visible "mouth", it is recommended that the aquarist feed them small shrimps or scallops and for smaller polyped specimens, it is recommended that specialised food such as Golden Pearls be fed.

Genetics

Lastly, the type of colours you want from a coral depends on its genes. If a coral has genes that makes it naturally brown, there is no use trying to colour it up. That's why you see people collecting specimens from all over the world to add special strains of corals to their stocks. Coral farmers are also looking into reproducing the special strains for distribution. Therefore, do not blame anyone when your yuma or stylo does not turn out as nice as other reefer's.

Copywright Dickson Goh 2005

good details.....