Raising erectis-one method

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A Scalable Method
of
Raising Hippocampus erectus
by
Dan Underwood
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FOREWORD
I have been asked by several people to write an article about our fry raising methods with H.
erectus fry. Initially I was hesitant. I would have preferred to have proven success and attained
some personal goals with the broods before attempting to write something significant. However,
people keep asking, and we have had some success. Our success rates seem to improve
with each batch of fry.
We do not by any means want to discount or take away from any methods used by others. This
method is based on our own experiences and objectives.
INTRODUCTION
Seahorse husbandry is still in
its’ infancy. There is still
much to be learned. There
may be several ways to raise
fry successfully. What
works for one species may or
may not work for another, or
it may work with some slight
modification.
Successful intensive culturing
of H. erectus fry requires
many resources. Aside from
the costs of tanks, filters,
stands, tools, test kits, salt,
frozen and live foods, electricity,
water, etc. it requires
a massive amount of time. We spend 14 to 16 hours a day, 7 days a week, working in our seahorse
room. Time is spent cleaning tanks and filters, feeding, preparing food cultures, testing
water parameters, record keeping, working on new setups, research and a lot of observation.
Fortunately we are a two person team who are both dedicated to this project. I do not believe
either of us could do this by ourselves!
Our initial attempts to raise H. erectus fry failed. We tried using small tanks and quickly became
frustrated. Despite all attempts, we just weren’t able to get fry past 4 weeks. We also
noted was that each brood were very labor intensive since we were splitting up the fry into several
small tanks.
Dissatisfied, we researched and experimented to come up with a feasible method that would
work for us. Our objectives were to have a simple system that would enjoy a high percentage
of survivability, minimal amount of maintenance, and provide scalability to support a larger operation
but still remain cost effective.

 

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After coming up with the method described in this document and putting it into effect, we immediately
began to have some success. As our experience increases and with small tweaks, our
fry survival ratio continues to improve. This method is simple, does not require the use of
green water, reduces the need for water changes and is easy to maintain. It is easily duplicated
and allows you to have several broods going at any time, provided that you set up more systems
and have adequate grow out space.
Hopefully this will answer most questions you may have regarding how we rear our H. erectus
fry.
BASIC SYSTEM DESCRIPTION
Initial Fry Tank - For an initial fry tank
we use a 15 gallon tall aquarium.
The goal was:
1. a tank that was inexpensive
2. had as much water volume as possible
with decent depth
3. could keep the food density reasonable
4. hold as many fry as possible.
The shape and water movement in the 15
gallon tall with this setup allows you to
have somewhat of a Kreisel effect. It does
not prevent fry from going to the surface.
However, it does gently force the lazy
floaters to go back down.
Since we were using a bare 15
gallon tall tank, we painted the
bottom dark blue so it would
be easy to see waste on the
bottom and have some contrast
so the fry could see the food.
These tanks are available locally
and are inexpensive at
$19.95 each.
Secondary Fry Grow Out
Tank (29 gal aquarium) - Our
choice here was based on
space utilization and price.
We stack the 29 gallon tanks
side by side to reduce the
Figure 2. Basic diagram of initial fry tank.
Figure 3. 2 week old H. erectus fry. Note the painted bottom.
The contrast makes it very easy to see a dirty bottom.
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amount of space needed. Using the same filtration scheme
as with the 15 gallon tanks. We have also placed some of
them on a larger 40-50 gallon sump system with multiple
tanks. In our experience both ways work well. On a larger
scale it is more practical to go with large sump system.
When the fry outgrow these, we then divide them up into
additional 29 gallon tanks as needed.
The Sump
We wanted as much filtration as possible without the problem
of fry being sucked up into the system. Another goal
was to increase the water volume used for stability. By opting
to go with a sump we can use any filter desired. The
only caveat to overcome was the problem of fry getting
sucked into the sump. This was easily handled by using a 1
inch standpipe with a sponge covering it.
Initial Fry Setup - We like having each batch of fry on their
own independent system for the first 3 – 5 weeks. This
seems to be where they are most sensitive and allows us to
treat each
batch as necessary
without
affecting other
batches. We
use 10 gallon
tanks as a
sump because of price, $9.00 to $10.00 locally,
and because it has the same footprint as the 15
tall. This way we can place it directly below the
15 on a stand either made from 2x4’s or wrought
iron.
Secondary Fry Grow Out – At this point we
have gone two ways, both have shown success.
We have continued using the 10 gal sump with
individual filtration and have also used a rack of
tanks on a larger sump system. It really depends
on the scale of the operation and budget concerns
as to which way to go.
Filtration
Initial Fry Setup - We went with the Marineland
Emperor 400 Bio-wheel filter which we get from
Figure 5. Picture of a basic fry tank. This
store bought stand makes sump maintenance
more difficult than a metal or 2x4
wood frame stand.
Figure 4. Initial fry setup on a
metal rack. Note the ease of access
and inspection of the sump.
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.
This allows us to have mechanical, chemical
and biological filtration in one unit. Some
may feel it is oversized, but so far it has done
well with keeping up the bio-load. There has
been some talk on another forum about bio-wheels
causing a nitrate problem. We have yet to see
this. Bio balls are also added to the sump, for
extra surface area for the beneficial bacteria.
These are loose and circulate in the water.
Kind of like a quasi fluidized filter.

 

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Secondary Fry Grow Out – on a small scale
the initial filter scheme as cited above works
well. We prefer to have a couple of separate
systems with multiple tanks on a larger sump.
This allows us to run additional equipment
such as UV Sterilizers and Protein Skimmers,
cuts down on some of the labor for maintenance
and becomes more economically feasible
when scaling up.
Tank Construction
Water Circulation
In using a sump we had to decide between an
overflow box or drilling the tanks. Overflows
take up space inside the tank, require more maintenance, run the risk of U tubes getting air
trapped in them and we worry about the fry getting trapped behind the boxes. We also found
that fry seem to get caught in the screen we placed around the overflows. Therefore we chose
to drill the tanks whenever possible.
Initial Fry Setup - After drilling the bottom of the tank a 1 inch bulkhead is installed. We
place the hole 4 inches from one end, centered and use 1 inch PVC for the standpipe. At the top
of the standpipe a sponge filter from the overflow boxes is installed. First, it is cut in half, then
covered with pantyhose to protect the fry from entering the sponge pores until the fry reach 7 to
10 days of age. The surface area of the sponge is much greater than that of the slits in the overflow
box. The water current in the drain is reduced and even with a 35 gal/hr flow, 1 day old
fry do not get plastered to the sides of the sponge.
To return water back to the tank from the sump we went with a Mini Jet 606 pump. We run ½"
ID hose from it to the tank. Instead of finding and purchasing a U shape return, at the top of the
tank, we run the tubing through ¾" PVC with 2 elbows. It merely hangs on the side of the tank
and requires no special brackets. A heater bracket can be used if securing it is desired. (See
Figure 5)
Figure 6. Another view of fry in a 15 gallon fry
setup.
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By placing the return line to the tank on one end and running an airline without an air stone on
the opposite end, a circular type flow is created in the tank. We have found that a flow rate of
about 20 to 25 gal an hour for the return works quite well in the initial setup.
Secondary Fry Grow Out - On the 29 gallon tanks, we went with a modified overflow design.
The placement of the tanks does not
allow for the bottom to have a bulkhead
and we are using cheap tanks, so
we were afraid to drill the sides or
bottoms. Our solution was to drill the
overflow box for a 1” bulkhead. We
come out from the bottom of the overflow
box with 1” PVC pipe to create a
U design that allows the use the
sponge again. The overflow box is
raised so that the only water coming
in, comes from the PVC. (See Figure
7)
Lighting
We use a cheap clip on utility light
from Home Depot. They run about $6.00. We use compact fluorescent bulb in the 7 to 10 watt
range. The light is clipped onto whatever is available so the it shines down at about the midway
point on the side of the aquarium and does not shine directly into the tank. This helps keep the
food more towards the center of the tank.
The light is left on for about 14 hours a day. Once the fry begin to take foods other than BBS
we move the light up to the top.r />
SYSTEM PARAMETERS
Water
After much research we opted to go with plain old city tap water. We gave a lot of consideration
towards RO water, but chose not to, due to the amounts of water needed and extra cost.
None of the local commercial hatcheries use RO water. They either used sterilized sea water
(location dependant) or tap water. So we use tap water that is either aged for 24-48 hours to degas,
or in a pinch, dosed with Sodium Thiosulfate to remove the chlorine.
Temperature
Tank temperature is kept at around 75 degrees F. Initially, we had it closer to 80 degrees. Although
ther were no specific issues, we are under the impression that cooler water leads to less
bacterial infections. Also identified, is that cooler water leads to a longer pregnancy. While
not having done any controlled studies ourselves, or know of any that have been done, the initial
survival rate (1st Week) seems to be higher with longer pregnancies.
Salinity
Salinity in all tanks is kept around 30 ppt (1.022 - 1.023 SG). We have tried higher and lower
Figure 7. Overflow box modification.
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salinities but have not noticed any impact in either the brood stock or the fry.
pH
Because we use bare bottom tanks, there is nothing to act as a buffer for the pH so occasionally
some buffer has to be added. On the larger systems with a sump, we have thrown crushed clam
shell in a porous bag into the sump. This seems to help keep the pH more constant.
Water Parameter Testing
Temperature and salinity are checked daily. pH, Ammonia, Nitrites are checked twice a week
or anytime something seems out of whack or if we just get a gut feeling that it needs to be done.
Calcium is checked about every two weeks.

 

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TANK MAINTENANCE
Each tank or tank system has its' own set of tools. We do not use them between different setups
to prevent any possibility of cross contamination. Also, there is a strict policy of washing before
touching any of the tanks, food etc and when going from one system to another.
Cleaning
We routinely clean the tanks twice a day. Once, before the first feeding of the day and again,
after the last feeding of day. Since we use bare bottom
tanks with a dark background this is done very easily. A
Micro Brush Vacuum Attachment is connected to tubing in
order to siphon and brush the bottoms of the tanks (See Figure
8). On the smaller fry we reduce the size of the tubing
down to airline size to slow down the flow and avoid sucking
up the fry. When cleaning the tanks with new fry we
use clean white buckets. This allows us to see any fry that
may have accidentally been siphoned out.
The filter pads on the Emperor 400’s and the larger sump
are cleaned weekly. The sponges on the stand pipes are
cleaned as needed which is usually daily with new fry, and
after several days with older fry or juveniles.
Whenever a setup becomes empty we tear down everything,
including the tank, hitching posts, tools, tubing etc, clean it
and soak it in Sodium Hypochlorite (Bleach). On the larger
grow out system we can’t tear down the whole thing, but we
do the same to each tank whenever they are empty.
Water Changes
In the course of cleaning the tanks we replace the water taken out, over the course of a week
this would equal between a 30% to 50% water change.
Figure 8. Micro Brush Cleaner
used for cleaning bare bottom
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FOODS
Copepods
When we have them, they are offered.
They are not practical in terms of maintaining
a sustainable culture for our
needs, so we do not rely upon them.
Rotifers
Probably not essential for H. erectus fry,
but we have them, they eat them, and we
have good survival rates during the first
two weeks, so we continue to offer them
the first few days.
Brine Shrimp
Baby Brine Shrimp (BBS) – San Francisco
Bay strain are used and decapsulated
before hatching. We have several hatchers and always have at least two going just in case
something happens to a culture. Larger cones are also available for rearing the BBS to several
days old as needed.
Adult Brine Shrimp
These are easily obtained from the local
live fish stores so we do not bother
to try to raise them.
CYCLOP-EEZE®
This is available freeze dried or frozen.
Although the freeze dried is more
readily available and cheaper, it requires
re-hydration, thus more work.
We have also found the seahorses
don’t take to it as well as the frozen.
So we use the frozen. It is a great intermediate
food and seems to make the
transition over to frozen mysis easier.
Frozen Mysis
We use the Hikari brand. It seems to be a good quality food, is clean and the pieces are typically
smaller the PE Mysis. We are now buying the 16 oz. flat packs in bulk.
Figure 9. Large 5.5 gallon culture cones used for both
brine shrimp and rotifers. Having a drain valve on the
bottom of both large and small culture cones is very
handy.
Figure 10. Small hatching cones for baby brine shrimp. We
also use them for enriching brine.
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HUSBANDRY
Birth
As soon as the fry are born, we use a plastic ladle to
scoop the fry out and move them to the 15 gallon tank.
We also take a count during this process and record it.
Generally we find it easiest if two people work together
doing this. One person does the moving and
the other keeps track with a notepad on the count. It is
very easy to lose count during this process.
We start with an initial stocking density of 15 - 25 per
gallon. We have had success on both ends of the
stocking density. If a higher initial stocking density is
used and a high survival rate is attained they do have
to be split out sooner for grow out.
Hitching posts are placed in the tank from the beginning.
H. erectus fry will hitch at night from birth.
The first couple of feedings are of Rotifers, newly
hatched BBS, and if we have them, Copepods are mixed in as well. We give the first feeding
immediately upon moving the fry to the rearing
tank.
Birth to 1 Week
During the first week the fry are fed Rotifers and
newly hatched BBS. At the beginning of the week
it's primarily rotifers and some BBS. By the end of
the week we are mostly giving BBS with Rotifers
mixed in. The fry are fed 4 to 5 times a day. We try
very hard not to overfeed. Our goal is to only provide
the amount of food that can be consumed
within 1 hour. Sometimes this takes a little experimentation
and observation. If we over or under
feed, adjustments are made on the next feeding until
we get it right.
1 Week to 2 Weeks
The fry are fed BBS 4 to 5 times a day without any
rotifers. 1 day old BBS enriched with Selco are
added to the diet.
2 Weeks to 3 Weeks
The feeding schedule of 4 to 5 times a day continues
but with a change to a mix of newly hatched
Figure 12. An example of high stocking
density. The fry in this tank are just under
3 weeks old and need to be split out to a
lower density
Figure 11. Fry at 1 week old.
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BBS and 1 to 3 day old BBS. The older BBS are enriched with Selco before feeding.
3 Weeks to 5 Weeks
Frozen CYCLOP-EEZE® are added to the diet of BBS. The CYCLOP-EEZE® are started by
adding small amounts at first then increasing the amount given based on how much of it they
eat. The CYCLOP-EEZE® are given about the same time as the BBS.
At 3 weeks we lower the stocking density to 7 - 10 per gallon. How this is done depends upon
the original brood size, survivability rates and availability of tanks. Generally we divide them
up into a second 15 gallon tank. We have moved them to the 29 gallon tanks before but prefer
the 15’s at this point.
5 Weeks to 7 Weeks
At around 5 weeks we begin to add enriched adult brine shrimp. Like the CYCLOP-EEZE® it
is started slowly at first, and
gradually phased in if it is
eaten. In the same fashion small
amounts of finely chopped frozen
Hikari Mysis are added to
the diet. When we begin to frozen
mysis we keep a sharp eye
on the water parameters. If you
overfeed and are not diligent in
cleaning up the excess uneaten
food an ammonia spike occurs.
By the 7th week almost all are
eating the chopped mysis.
Around 7 weeks we move the
fry to a 29 gallon grow out
tank(s) with a stocking density
of 3 - 4 per gallon.
7 Weeks to 10 Weeks
We continue with the feeding of the chopped mysis and the Selco enriched adult BBS.
By the 10th week, typically a second 29 gallon grow out tank is needed as we reduce the stocking
density to 2 - 3 per gallon.
10 Weeks to 12 Weeks
We continue with the same feeding regimen as in weeks 7-10. By the 12th week some of the
males begin to develop their pouches. Although the pouch may not be visible initially, there is
usually a darkened area of skin where the pouch will soon begin to grow.
Also during this time frame we sort out the smallest of the brood and place them in their own
tank. These seahorses are much smaller than the rest. By moving them they do not have to
Figure 13. Feeding time for 13 week olds.
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compete against the larger horses. Many will take off in a growth spurt, some just do not seem
to grow despite the change in conditions.
12 Weeks to 14 Weeks
We continue feeding the frozen mysis. We also begin the converting them to 3 feedings per
day. This is done by dropping a feeding per day each week.
14 Weeks to 17 Weeks
We begin separating the Males and Females. Depending upon the size of the brood, another 29
gallon tank may be employed as we reduce the stocking density to 1 - 2 per gallon..
By the 17th week we are ready to start shipping the seahorses to their new caretakers. After the
17th week, we maintain a stocking density of about 1 per gallon.

 

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HELPFUL TIPS
These are some of our observations. While they may not work for everyone, they do work for
us.
• Read everything you can find on breeding seahorses, but don’t believe everything you read.
Seahorse husbandry is still in its' infancy. An article just a few years old can be outdated
irregardless of the author. However, you can pick up ideas and information. You will have
to assemble the information and test it for yourself.
• If you can not devote full time attention to your fry, consider working with a small batch
with a lower stocking density.
• A larger the volume of water used for the system, creates a more stable environment for the
fry.
• If you are going to run a bio-filter consider not using greenwater. It can clog you filter and
will increase the bio-load.
• Keep records of each batch. After a few batches it is very easy to forget and confuse data
with different batches.
• Always have extra saltwater mixed, aged and ready to use. It will be easier on the fry if you
have to do a sudden water change.
• If you are relying on water changes instead of bio-filtration, consider several smaller water
changes instead of one big water change. There is less likelihood of shock this way.
• H. Erectus fry are benthic and hitch from birth. Make sure you provide adequate hitching
material.
• Never mix the fry tank tools and materials between systems.
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• Decapsulate your brine shrimp eggs. One round of hydroids can wipe out your fry.
• If you are having a tough time, seek support for morale. You may find it will take several
attempts before you are successful.
• Always overlap when changing foods. Not all the fry will convert at the same time.
• If you are having a hard time switching to frozen mysis, try adding some enriched adult
brine shrimp. This helps the fry get used to a larger food.
• With high stocking densities, watch your water parameters closely when changing to different
foods, especially frozen foods.

 

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