- Can we make additions to the diet that we feed our fish
that would make them more colorful
while keeping them healthy?
Would a diet geared more towards coloration
have any impact on the nutrition
that Clownfish just need to grow and survive?
There's a new paper out in Aquaculture Nutrition,
and they studied exactly that in Ocellaris Clownfish.
Hi guys and girls, I'm ReefMan,
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if you like this sort of content.
Let's dive in to this paper.
The paper is called Effects
of Natural Dietary Carotenoids on Skin Coloration
of the False Clownfish Amphiprion Ocellaris.
And they're looking for a way to safely brighten
the coloration of captive bred Clownfish
while ensuring that they grow well
and are still generally healthy.
Clownfish, like a lot of other fish,
are not able to make the chemicals
that lead to their yellow, orange, and red coloration.
Instead, they collect these chemicals
from their food and from the environment around them
and they use them in their skin
for the colors that we see on the fish.
Chemicals like tuna xanthin,
which is actually found in albacore tuna, hence the name,
doradexanthin, and lutein,
which is present in many species of algae,
they all help the fish with their bright yellow colors.
Beta carotene, zeaxanthin,
and canthaxanthin lead to brighter oranges,
and things like astaxanthin are responsible for reds.
So there's different chemicals for different colors.
While fish can, of course,
create some of these chemicals themselves,
others, including Beta carotene and lutein,
they have to be present in their diet
for the fish to be able to achieve their bright skin colors.
Beta carotene can also turn us orange
if we eat too much of it,
and it's found in things like carrots,
sweet potatoes, things that are orange,
and our bodies actually need it to create Vitamin A.
Out of necessity, Clownfish are fed commercial diets
in the facilities that breed them
for the captive aquarium trade,
and of course, when you're at the local fish store,
if you have the option between
a brightly colored fish and a dull, drab fish,
you're gonna pick the brighter fish most of the time.
So what if we could just feed
the Clownfish in these breeding facilities
something like a carrot or a sweet potato,
something that might be just
an easy way to brighten their colors,
which would lead to the captive bred fish
being more attractive and better suited
to the market like wild Clownfish are.
In this paper, the authors studied exactly that question.
They used four different diets
and then they compared the coloration
and the growth of the fish after eight weeks
on each experimental diet.
I do wanna point out that the health and the growth rate
of the fish overall was pretty much
the same in all of the diets,
so it does seem like all four options
that they use in the paper
are reasonable things to feed Clownfish in captivity.
So the paper just focuses on coloration,
so that what I'll focus on in the video,
'cause that's where the difference is.
The first diet that they looked at
was just a commercial food
for Angelfish and Discus, things like that.
It's called Angel Feed and it's from
a company called Duong Bac Company.
Now I should mention that this paper
is from a team out of Thailand,
so please excuse my pronunciation, I don't speak Thai.
This commercial food, it's used as
the reference diet in the paper,
because it's just generic.
It does contain many of the ingredients
that are supposed to enhance coloration
of the fish that it's targeted for,
so Angelfish, Discus, these kinds of things.
And it's just used in breeding facilities
for these fish, and hopefully they look better for it.
Altogether, diets that they use
are referred and compared back to that original diet.
The second diet they used is called
the moist diet in the paper,
and they created it by grinding up fresh beef hearts.
They ground it up with other ingredients,
like spirulina until it was a consistent paste,
and then they kept in the freezer
until it was used to feed the fish.
There is a generic paper,
I'll put the information down below.
You can read all about that.
But it's just a generic diet used
to increase the overall coloration
of the fish using beef heart and spirulina.
The third and fourth diets that they tested
were custom made ones.
The first one was from sweet potatoes,
and then a second one was from an algae
called Gut Weed or sea lettuce.
Now both of these things are very high in carotenoids,
so perhaps they'll be a good source
of carotenoids for the fish that eat them.
In both cases, they've combined the sweet potato
or the algae with fish meal and other ingredients
so that it would be a complete meal,
and then they extruded it and made it into pellets,
and then they dried the pellets,
kept them in the refrigerator
until they fed them to the Clownfish.
So it's an interesting thing.
I wonder if we should keep our pellets in the refrigerator.
Something interesting to think about.
So they fed the fish one of those four diets
for eight weeks consistently,
and then they measured the coloration
of the fish in three different ways.
They measured it visually just by looking at it.
They had 20 volunteers,
they used photos and a computer
to evaluate what color and how intense the colors were,
and they also tested the amount
of Beta carotene in the skin of the fish itself.
Now they found that the level
of red pigment in the fish varied significantly depending on
the diet that the fish was fed,
while yellow was not affected much at all,
which was an interesting finding.
It can impact the orange and red,
but no so much of the yellow.
The best performing diet for the levels
of Beta carotene in the skin
was the one containing sweet potatoes,
and then depending on the measurement method,
either Gut Weed or the moisture diet,
which was using the beef hearts, was the second best.
Now you can see the results here.
I have 'em on the screen.
In the results, a higher score is better
and it means that the fish was brighter
in both color and in Beta carotene level.
I think that this is a really interesting paper.
There is a link below if you want to read it yourself,
though unfortunately, it's not open access.
Now I've always heard
that you can feed your fish special foods
to increase the brightness of reds and oranges,
but I've always thought, meh, maybe,
doesn't really make sense to me, but okay.
And then I've never actually read
a paper specifically testing it in reef fish.
But now we have one.
And it's nice to know that this isn't all
just sort of marketing mumbo jumbo
and random people on forums,
and that it actually is based in fact
and you can feed your fish something
that will have an impact on their coloration.
It's also really nice that the authors chose
to use a readily available natural source
for all of their test foods.
A lot of other papers used synthetic carotenoids
in their feeds and that's a lot harder
to get than a sweet potato
that you could buy at the grocery.
So maybe I'll grind up some sweet potato
and add it to the mix of food
the next time I make some frozen food for my reef tank.
So maybe sweet potato squid, anyone?
That's it this week.
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Thanks for watching.
I will see you next time.
Bye!