smaller than females and they are also
much thinner and more streamlined. So,
females are usually a bit larger than males,
and they are plump and more rounded. If
you are interested in breeding this fish, you
should aim for a ratio of two males to one
female in the group.
Once you have selected healthy stock,
you still need to get them home. This can
be very stressful for the fish involved, but
there are a few things you can do to help
make it easier on them.
The first is food. These fish were probably
fed flake food in the store, but Otocinclus
are vegetarians. When going to purchase
my otos, I usually bring a piece of finely
cut, skinned cucumber or zucchini. Before
the fish go into the bag, I drop in the
vegetable piece so they have a treat to snack
on during the trip home. The transfer is
still stressful, but food and stress relief
go hand in hand. (Now where are those
I bring a dark plastic bag or some other
dark container to put the bag of fish into
to block the light. In the absence of light
and the presence of food, your Otocinclus
can relax for the ride home. Another
consideration for a carrying container is
travel distance. If you are going to be
traveling very long, think about bringing a
small cooler to maintain proper temperature
in the bag.
And remember, no stopping for lunch or
errands on the way home. Your fish should
be transported directly to your aquarium.
Their New Home
Finally you have the Otocinclus home, and
you wish to introduce them to your aquarium.
Remember, one week ago these guys were
probably swimming in some tributary of
the Amazon. Being a South American fish,
coming from a wide range of water sources,
most Otocinclus can live in a variety of water
conditions, but to have them thrive and
reproduce, coming close to their optimal
conditions is recommended. Fortunately it is
not difficult to provide these.
Water temperatures in their native ranges
(depending on the species) will go anywhere
from 66° to 82°F. Usually as a safe range, I
prefer to keep the water around 75°F. The
pH of the water can also differ from locale
to locale, but a pH range between 5.0 and
7. 8 can be handled. Anything over pH 6. 8
will likely eliminate the possibility of the
Otocinclus breeding in your tank. I’ve kept
Otocinclus vestitus in a pH of 5. 6 without
any problem. As always, proper acclimation
is the key to success.
Since Otocinclus prefer soft, acid water, it
is a good idea to add peat granules in the
filter, peat moss as an initial layer under the
substrate, driftwood for releasing tannins,
or a blackwater extract. The softer the
water, the more willing they are to breed.
A small current in the tank will help your
Otocinclus, as they require well-oxygenated
water. I prefer to keep small powerheads
in larger tanks to create some current, and
to kill any stagnant spots in the tank. A
powerhead is not necessary, but remember
to provide some water movement.
The quality of your acclimation procedure
can either make it or break it for your
newly acquired Otocinclus. Mine is the
same procedure that I use on my saltwater
fish. Float the bag for about 10 minutes to
adjust the temperature. Afterwards, empty
the bag with the fish into a small plastic
or glass container and gradually add small
amounts of water from the tank. When
the volume has doubled, move the fish
into their new home and discard the water
in the container. Unless your water is
totally different from your LFS, this process
does not really take long, but it is time
well spent. One of the biggest killers of
Otocinclus is improper acclimation.
I acclimate with the tank lights off.
Otocinclus are nocturnal to begin with, so
getting used to their surroundings in the
dark is a preferred and more comfortable
method. This also prevents the tankmates
from being too curious about the new fish
and gives the Otocinclus time to settle in.
As for those tankmates, common sense
should prevail. If you have a gut feeling
that a fish might not work with your
Otocinclus, go with your instincts. Fish that
are obvious predators should be avoided,
and research is paramount. Talk to other
hobbyists that own the fish you want to
get. The online forum where I serve as
a moderator, Tropical Resources (www.
tropicalresources.net), is a wonderful place
to ask questions and get help.
Tank Decor and Setup
Setting up a tank to keep Otocinclus
happy can be fun. Tank design is
extremely important to consider. The
areas where Otocinclus come from are
Otocinclus spend much of their time seeking
food, with their mouths leading the way as
they graze surfaces (such as plants and wood)
usually fast-moving rivers and streams.
Large floating islands of vegetation are
magnets for Otocinclus. Not only do these
contain plants, but all sorts of infusorians,
Daphnia, and other micro-bugs that all
fishes feed upon.
I personally always like to add wood to
my setup. Though Otocinclus do not rasp
like some other loricariid species, they do
relish the algal growth that wood attracts. I
find also that if the wood has notches and
curls, otos will gather there and use it as a
central spot for the colony to reside in. The
social behavior is more apparent with more
natural decor in the tank.
Rocks are relatively unimportant. Though
they are great surfaces for algal growth, I
find that Otocinclus prefer grazing on algae
growing on the wood and glass as opposed
to rocks. If you do consider adding rocks
to your tank, ensure that rough and sharp-edged rocks are omitted.
Otocinclus like to swim in groups if you
have enough of them. I have a grouping of
25 that move 12 or 14 at a time, leaving
a few stragglers behind only for a short
while. So, like most fish, they need some
space for swimming.
The basic setup should include some
hiding spots (natural ones if possible) in
which your Otocinclus can retreat for cover.
As these are skittish fish that dart at the
slightest movement in the room, it’s best to
provide refuge areas such as holes in wood,
or hiding places in the back of the tank.
Heaters should have guards around them
as well. I’ve lost a few Otocinclus due to
them sucking on the heater. Filters should