Produce more fish with less feed…

Produce more fish with less feed…


Hello sustainable growers. This is Jonathan from Melbourne Aquaponics. Today, we’re going to talk about the feed
conversion ratio which means the quantity of food that we need to grow one kilo of fish. So in aquaponics, we are growing fish and
we are doing it because we just love it. We have the fish ready in our backyard. We can see them. It’s really fun but there is also a real
sustainability to reach. You know, we want to have a system that is
very, very sustainable. We want to grow some food with the minimum
of impact on the planet and the minimum of impact on our finances as well. You know we don’t want to spend too much money
to grow one kilo of fish. We want to be basically efficient from the
financial point of view and from a sustainable point of view. So in aquaponics, one of the big costs is
the price of the fish food. You know that in aquaculture it represents
50% of the cost of the fish is represented by the fish food and the reason why is because
this fish food is processed and is made thanks to some fish that are caught in the sea and
also it’s dry. So when you buy one kilo of fish food actually
you got the equivalent of 5 kilos of fish food because the fish food that we buy is
only 14 — I mean between 8%-14% moisture, while a fish is 75%-83% moisture. So you see there is a big ratio and actually
the total weight of the fish food when we got one kilo of fish food we have actually
the equivalent of 5 kilos of normal material, normal fresh fish, normal fresh vegetables. So you see that there is — we give a lot
of fish food to our fish and the most important thing to know is to make sure that this fish
food is going to be well used by the fish. You don’t want to waste the food. So there are a few points that we’re going
to talk about today that are going to be able to basically if you focus on the point that
I’m going to give you you’re going to be able to improve the feed conversion ratio of your
fish, which means that with one kilo of food, you may be able to produce one kilo of fish,
and you may even need less than one kilo of fish food to produce one kilo of fish. So the number 1 point to focus on is the way
you feed your fish. When you distribute the food, you want to
make sure you send the food everywhere on the surface of the fish tank. You want to make sure all your fish have access
to this fish food. If just a few of them have access some of
them are just going to push the others away and the small ones are never going to have
access to the fish food so they’re going to stay small and therefore, they are not going
to be able to grow and therefore, you just spent on food for nothing because the fish
are still going to eat a bit of food but not enough to grow. So you know that when a fish is eating it’s
going to use the energy for different things. The first thing it’s going to use the energy
to maintain the metabolism and you know all the cells in their bodies they need energy
to stay alive and those cells even if they don’t grow, they’re going to consume some
energy just to maintain the system And then you got the activity of the fish. The fish need to swim, they need to basically
face any stress so all those things they consume some energy. So that’s just point number 2. Number 3 you got the growth of the fish. The fish is going to eat and it’s going to
grow. It’s going to basically build his body and
the point number 4 is stock. You know, the a fish is going to basically
save some energy under the shape of lipids so you’re going to have some lipids that are
going to be stocked in the fish same as humans you know you got some humans that are fat. It’s because we stock the energy. When we eat enough for our needs then we stock
the energy. So the fish are the same. So what you want is to fulfill the three first
ones so if the three first needs and not too much of the fourth because then you’re going
to have a fish that is very fat. It’s not the best to eat. So you understand that if you fulfill those
three first needs that’s okay. You’re going to have a fish with a nice growth. If you fulfill only the two first ones that’s
where the fish are going to stay alive but they are not going to grow so they’re going
to consume some food here, some food to fulfill those two needs but not enough to grow. So basically it’s like throwing food away
because you’d give some food to your fish but they don’t grow. So it’s really useless and this can happen
if you feed your fish but not enough. So make sure that when you feed your fish
you feed them enough and they can grow. So I made a special video about how to feed
your fish in aquaponics. Please have a look. It’s going to give you all the information
that you need to basically feed them the best way possible because the feeding techniques
where you distribute the food on the fish tank is very important but then also there
is a frequency. Fish need to be fed quite often. You know, if you feed them once a week it’s
not enough. I mean they’re going to stay alive but they
are not going to be able to grow properly. The best thing to do is to feed them twice
a day if you can. So the quality of the food that is used is
also very important. You know that the fish they got some specific
requirements in terms of food quality and if they don’t find what they need, they may
basically just not grow up properly. It may limit their growth and in this case
same thing. You are not going to use — you’re going to
spend some money and some yeah, you’re going to spend some money into a specific quantity
of fish food but you are not going to have the best growth of your fish. So the fish food quality needs to be adapted
to the specific species that you are growing. Another point is the size of the fish needs
to be the same. So all your fish need to have the same size. You know in aquaculture the fish farmers they
are spending a lot of time just sorting the fish. Basically a fish farmer is spending time to
feed the fish and to sort them. So when they sort the fish they’re going to
sort them per size and they’re going to put all the small fish together, all the big fish
together. When they do that they avoid to have this
territorial behavior where basically the small fish can’t have access to the food because
the big ones are pushing them away. So that’s what happens when you got fish that
can’t have access to the food as I was just talking about before. He’s going to fulfill his two first needs
just to stay alive but he’s not going to grow and therefore, you lose a lot of time. You lose a lot of money. So the fish need to be sorted in aquaponics. If you see that you fish have got different
sizes if you got some big fish and small fish try to separate them. If you got different tanks put them in different
tanks. If you don’t try to keep either the small
ones or the big ones and sell the others or eat the others or give the others to someone
but basically don’t keep fish of different sizes together especially if they are aggressive
fish. Depending on the species, you may allow yourself
to do it. If it’s carps fish like this you know that
are not too aggressive you can keep them together but if you got predatorious fish, territorial
fish basically when you put some food in the tank, they’re all going to jump to the surface. The small fish most of the times they can’t
jump to the surface. They can’t basically face the big ones. They can’t just find the food and they are
just going to have the leftovers and basically they are not going to grow. So really focus on trying to keep your fish
all of the same size. And finally if you want to keep a good feed
conversion ratio you need to focus on growing fish that are quite small. So it’s quite simple to understand. If you have small fish they’re going to take
a very short period of time to double their weight. Right? So if you have fish from 20 grams to 40 grams
it’s going to take only a few weeks but for a fish to grow from 1 kilo to 2 kilos they’re
going to take months So you understand that you grow more fish when you got small fish
than big fish and therefore if you are growing your fish in aquaponics, focus on growing
them not too big especially if you reach the maturation point. So I made specific videos about it. Have a look at the video how to maximize the
fish production in aquaponics. In this video I talk about the maturation
of the fish, how basically when they reach a certain point, they put a lot of energy
into the gametes into the basically the sexual products such as the sperms and the ovules
and therefore the growth of the fish starts to decrease and therefore the growth of the
fish starts to slow down. Another point that is very important is to
maintain an adapted temperature. You can’t have a good growth of your fish
if the temperature of the water is not adapted to the species you have. So basically depending on where you live if
you have an aquaponics setup outside please just use — just try to grow species that
are adapted to the area where you live. If it’s not the case either the fish are not
going to grow, either they’re going to die but basically you are not going to have a
good conversion and your system is not going to be efficient. It’s not going to be sustainable. So try to grow local fish that are very well
adapted to the water temperatures that you’re going to offer them. And final point make sure that the oxygen
level is going to be at a good range. If you don’t have enough oxygen in your
water the fish are basically not going to be able to digest their food properly and
therefore they are not going to eat more. They’re going to lose their appetite. So you want to make sure you got enough oxygen
in your water. For that you can just put a little air pump
just on the side of the setup with an air stone and in this case it’s going to add
a lot of oxygen to your water and you’re going to be sure that your fish are going to be
growing in good conditions and they’re going to eat properly. So in conclusion, you could see that there
are a lot of factors that can affect the feed conversion ratio but basically you need to
make sure that you give the best conditions to your fish to make sure they will absorb
the energy properly and convert the energy into growth, into basically muscles, into
flesh. So now how do you calculate the feed conversion
ratio? Well, that’s very simple. On the very specific lapse of time let’s say
two months you see how much your fish have grown and how much food you have used to grow
this quantity of fish. So if in two months you have used two kilos
of fish food and you have grown one kilo of fish you divide the quantity of fish food
by the quantity of fish that you have grown in terms of kilos. So you have 2 divided 1 is your feed conversion
ratio is 2 which is quite bad. What — I mean it depends. It can be good depending on the species actually. For vegetarian species it’s good but for predators
such as trouts it’s quite bad. A trout can have a feed conversion ratio as
low as 0.9 which is you can use only 900 grams of food to produce one kilo of fish. So you can see the difference. In one system we use twice as much as the
other system. So just focus on the food conversion ratio. It’s going to allow you to limit the quantity
of fish food that you use and therefore it’s going to be better from a financial point
of view and from a sustainable point of view. So if you are new to aquaponics, don’t forget
to get the free guide to build your own aquaponics system from the description just below. It’s a six-step guide that helps you to
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a fantastic success with aquaponics. Have a good crop!

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