Once you have successfully created an environment
where the fish have spawned and the eggs have been harvested and the fry removed from
their hatching containers, there is still a long way to go. But it's some of the most
rewarding and fascinating part of the process.
Now the process may sound a little cruel is
a way, but there is a method to our madness and ultimately it results in more fish than
most methods. We are interested in both the quality and the quantity of the fish we raise.
The quantity is important for a couple of reasons. Not only do we want to be able to
market a few of the fish, we want to have enough survive the process so that we can
continue to breed the species. If the process does not result in enough fish, the species
may not survive in our hatchery.
Once the fry are extracted
from their hatching container, we place them in plastic shoebox with about 1/2 inch of
water in the box. We don't use any treatment in the water but do place a small snail and a
wad of java moss in the box. The snail helps with over feeding and the java moss provides
some small foods and cover for the fry. We stack the shoe boxes and feed the fish through
holes cut into the end of the boxes.
Of course, like everything in the Killifish world, we are careful to label all of the
containers. Now that the fry are boxed up in shoeboxes we might not see them for a week at
a time. It is important to keep information as to the number of fry in the container along
with the species into. We also note the date of the harvest so that we can keep track of
growth rates. We have found it helpful to use colored self adhesive dots on the ends of
the boxes to denote what types of foods and the relative quantity of food to feed a box.
When we travel it is much easier to train a person how and what to feed with the color
coordinated dots applied to the boxes. We use the same system for the tanks also.
You can see in the photo that
the boxes may have a couple of holes in the end. The boxes have several purposes other
than for fry. We breed fish in them also. The holes are actually melted through the
plastic with a heated piece of pipe. The larger holes may have a cork in them to prevent
the fry or adults from leaping out. We feed through the smaller holes.
It is very important to change
water in these boxes on a regular basis. We might keep as many as 75 fry in a single box.
With that sort of bio-load it is imperative that the water is changed frequently. We find
that is take only a couple of weeks before the fry are too big for the limited space
provided by the shoebox. So, if it's such a short period of time, why use the boxes in the
first place?
We have found that the fry are
a lot easier to feed and care for if they are kept in a small container for a short time.
The shoebox is easy enough to clean and the fry are concentrated enough that they can find
the small quantities of food that we feed.
For the entire time the fry
are in the shoeboxes they are fed a diet of freshly hatched baby brine
shrimp...generally...twice a day. We're human, we do skip a feeding from time to time.
When the bio-load warrants,
the fish are transferred into larger boxes, commonly referred to as "sweater
boxes." They hold about 3 gallons of water and, like the smaller 1 gallon shoeboxes,
they can be stacked.
You will note that the boxes
in the photo have a drainage system and several holes melted through the end. We have set
up the system to allow us to add water in one hole, add air through another and feed
through the third. The drain pipes the water through the wall of the fishroom and into the
garden. The blue gang valves are plumbed into the central air system. We use a blower in
the hatchery so we have plenty of air. The sheets of wood are used to help prevent the
boxes on the bottom from collapsing under the weight of the water. Remember, these boxes
were not designed to hold water nor to be stacked in this manner.
When the fry are moved into
one of these larger boxes we usually pour them in using all of the water from their
previous shoebox. We add a snail for the volume and double the amount of water they are
in.
Over the next several weeks we
double the amount of water each week until the water starts to run from the overflow
system and then add 2 liters of water once or twice a week depending on the bio-load of
the box.
The inside of the over flow
system has a screening on it so that even the smallest fry we would be transferring will
not be washed away.
Like the shoeboxes, we use a
system of colored dots for feeding info. Also like the shoeboxes, we carefully label the
sweater boxes and add information to the label that we might find useful down the road.
Fry might stay in this part of
the system for a month or more. About the time the fish are 1/2 inch long, we move them
into a 10 gallon glass sided tank for either completing the grow-out or as the last
interim home. If the particular batch of fish is too large for growing our in a 10, we
move the entire batch into a 20 where they will compete their growth.
The boxes are more revealing
than you might think. While we might not be able to see the color of the fish, we can seen
the size of the fish through the translucent plastic. When we are adding new fish into the
system we take a moment to remove the lid of other boxes as they become exposed. We take
the opportunity to check on the total health of the fish in the box and make additional
notes on the end.
When the fry are added to the
sweater boxes they are on a baby brine shrimp diet. When the fish are large enough, we
added Grindal worms to their diet. About the time they are all able to take Grindal worms,
they will be the magical 1/2 inch size and be moving to a 10 gallon tank. Like most of the
fish in the breeding program, the fry in the sweater boxes are fed...generally...twice a
day.
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