food. This is where major amounts of algae
RAISING THE FRY
I’ve had broods of up to 20 eggs, with
17 fry hatching; but after two weeks, I am
usually down to 9 or 10. I’m not sure what
causes such a high mortality rate, but I
think the environment is a major factor.
The next time I attempt this, I am making
sure that the tank is totally covered in algae
(diatom or brown smudge) to see if this has
an effect on rearing more fry to maturity.
Even some extra foodstuffs, such as small
pieces of veggies, might be an alternate
At one point I had a colony of six, which
peaked at 35, and then the tank totally
crashed. All the algae eaters (minus the
Amano shrimp) perished. I suppose all
the food sources were depleted. It’s very
important to maintain food sources and
clean water for the Otocinclus fry.
The fry are miniature replicas of their
parents. Keeping them healthy requires
some intervention and some care. The
major concern with the fry is their small
size and the availability of food sources.
Growing algae logs is usually a good start
to help these little guys out.
Water purity is a definite must as well.
Ten-percent changes daily with prewarmed, pre-treated, and pre-aged water
is a good start. You can use RO/DI water
mixed with regular treated tap water for a
mineral source. If left alone, your mortality
rate will be a little over half. With good
water changes, I’ve had a mortality rate as
low as 10 percent.
Keeping the fry in their breeding tank for
the first few months is very important. Due
to their small size, they will soon become
quick snacks in a community tank. I wait
until they are about ½ inch before moving
them to a grow-out tank.
The grow-out tank should have the
same water conditions as the main tank,
minus a substrate. I do keep plants in
there, but I keep them in pots rather than
planted in the substrate. At this point,
I start to feed vitamin-enriched foods
and algae logs. You should notice your
fry starting to grow quickly in such an
environment. The breeding tank should
be restocked with algae if you want more
breeding to continue.
When your fry are an inch in length
you have the option of moving them into
community tanks, where they will become
excellent scavengers and little cleaners. I
suggest keeping the breeding and grow-out tanks running at all times. Even when
there are no Otocinclus in either, it’s good
to let the tanks mature, to provide algae for
when you decide to raise another colony.
I’ve done this many times, as I’ve had
some population crashes and learned some
Summary and Conclusion
With this species, food determines
survival. Both fry and adults can starve to
death if the supply of algae fails. Otocinclus
love water movement, which provides both
oxygen and a play area. This fish demands
the highest possible water quality, so have
great filtration and do plenty of water
changes. For breeding, you should have your
fish in a species tank—a colony of just otos.
Breeding and rearing Otocinclus can be
a rewarding experience, but it requires
some tank space, some patience, and some
knowledge on your part. The end result is
that once your Otocinclus start breeding, it
becomes a regular occurrence.
Hopefully I have been able to convey my
appreciation for these endearing little guys
and gals. They are industrious and playful,
all in one package, and peaceful little algae
eaters and tank scavengers.
A future project for me is to try to breed
Otocinclus cocama (zebra Otocinclus), a nice
fish with a big price tag. I would also like
to thank the people (both staff and users)
at Tropical Resources for encouraging me
to publish this article. Thanks also go
out to Paul Apgar at Otocinclus.com, for
information and feedback. I appreciate all