It doesn’t matter which species of
Otocinclus you own, they all require the same water conditions
- low stock density and pristine water - depending on your water
source, you may want to use an RO system. You’ll need a
mature filter capable of cycling your aquarium water at least
four times an hour (GPH rating). Keep nitrate levels between 0-20ppm
(parts per million) and have no measurable ammonia or nitrite.
Otos prefer a stable pH, which is neutral to slightly acidic (6-7.5)
and a water temperature between 72-82°F (22-28°C) Stock
your tank with plants (see more info below) and perform weekly
25-30% water changes to help keep your water as clean as possible.
Water Quality Overview:
- Filter with a
GPH rating 4x the volume of your tank.
- Nitrates between
- No measurable
ammonia or nitrite.
- Water Temperature:
- pH: 6-7.5.
- Water Hardness:
6° to 15° dH.
Otocinclus are social fish, living
in shoals of thousands in the wild. Because of this, you’ll
need to keep at least 6 in your tank - 10-15 would be better.
Preferably in a 20-gallon tank, however, if you only want to own
6 Otos a 10-gallon tank will be okay.
We both know water quality is vital, so I recommend you use a
canister filter with a GPH rating 4x the volume of your aquarium.
You’ll also need a good aeration and sufficient water circulation,
so try adding a water and/or air pump. You’ll need appropriate
LED lighting for your plants - you can see more information here.
As well as a CO2 injector and test kits to keep track of the ammonia,
nitrite, and nitrate levels in your aquarium.
Pre-soaked branches or bogwood and rounded stones will provide
your Otos with areas to graze. Be careful, make sure you avoid
any objects with sharp surfaces. Your Otos (and other fish in
your tank) may damage themselves and create the ideal environment
for disease to establish.
Your Otos will graze on algae from your plants, so I recommend
you use slow-growing plants. Fast-growing plants will often consume
the carbon dioxide and dissolved nutrients before algae get a
chance to feed and grow.
Here are some slow-growing plant
species you can use:
- Cabomba (mimics Otos natural environment)
- Java Fern
- Java moss
Otos: “a Fat Oto is a Happy Oto”:
Otos love to constantly graze on soft green algae growing on your
substrate, decorations, aquarium glass, and plants. You don’t
want to confuse soft green algae with Green Spot Algae. GSA is
extremely tough to remove and Otos won’t eat it. Hobbyists
have also reported Otos eating Brown algae (Diatom), which can
often appear in new aquariums which haven’t matured. - If
you want to learn more about different types of algae, you can
see a detailed guide here. Now, this is important, and you should
take note of this: Most aquariums with a stable ecosystem will
not produce enough algae to sustain 6+ Otos. Because of this,
you need to provide some extra food. You can do this by feeding
them algae wafers or Catfish pellets. You can also supplement
their diet with blanched vegetables, Brussel Sprouts, Romaine
Lettuce, Spinach and Zucchini (Courgette). When you’re feeding
your Otos blanched vegetables, you’re going to need to weigh
them down so it’ll stay in one spot long enough for them
to reach it. You can do this by using a Veggie-Clip, leftover
plant weights, or attach it to a small rock using a rubber band.
As a general rule, don’t leave
the vegetables in your aquarium for more than 3 days. Pro Tip:
Thoroughly wash the vegetables - make sure they’re free
of pesticides before you introduce them to your aquarium.
Sexing and Breeding Otos:
It can be difficult to sex Otos because there’s no obvious
distinction. But, if you look closely the females are slightly
larger and wider than males. And when it comes to in-tank breeding,
it’s rare - but not impossible. If it happens, aquatic hobbyists
don’t tend to notice until they’re greeted by their
new friend in the tank. If you’re one of the lucky ones
who manage to witness the mating process, you’ll see the
female swimming up and down plants, rocks, or the sides of your
tank with males in hot pursuit (pun intended). A lucky male will
then get into a ‘T’ position with the female - causing
her to release and hold her eggs with her ventral fins. After
the female has found a suitable surface to place the eggs, the
male will fertilize them. The process is then repeated until the
female’s done. You can read a successful breeding story
here. Unlike other Loricariids, Otocinclus males do not
guard their eggs.
Buying Otocinclus - Be Warned!
A HUGE problem with keeping Otos is the first month of ownership.
It’s common for hobbyists to report high loses in the first
few weeks - even in ideal tank conditions. So what’s going
on? Well, there are a couple theories…
A lot of hobbyists in the community believe the trouble starts
during their capture. It’s believed that fishermen use chemicals
like Cyanide to slow down or temporarily paralyze the Otos. They’re
then easily able to gather large numbers of fish. However, cyanide
fishing is more common in reefs. And, I would like to point out
I cannot seem to find any official online reports about fishermen
using Cyanide or other chemicals to catch Otos - if you know of
any, please share.
Shipment and Starvation?
The stress put on fish during shipping can be handled by strong
and healthy fish. However, Otocinclus species are famous for being
subjected to some awful shipping conditions. Temperature swings,
oxygen changes, irregular light cycles, dramatic movements, and
vibrations can cause a number of diseases to infect the poor fish.
Starvation is a big problem because they’ll secrete the
nitrogen in their food via their skin and gills as ammonia/ammonium
- toxic to fish. It’s not uncommon for them to be starved
for 24-48 hours before the final bagging for shipping. Having
been used to an environment with plenty of algae and plants, they’re
then starved and left in a bare tank - it’s no surprise
there’s often many DOAs (Dead on Arrival). The fish then
arrive in the fish store, where they’re commonly kept in
overcrowded tanks with little algae to feed on. If the pet store
doesn’t provide them with algae wafers or vegetables they
won’t last long. It’s not a case of Otos being a fragile
fish, it’s the fact they’re generally kept in harsh
conditions before they’re bought. But,
it’s not all doom and gloom - you can use to following tips
to buy healthy Otos.
How to Buy Healthy Otos?:
To avoid the disappointment of losing your lovely Otos in the
first few months, it’s important you pick the healthiest
Otos from your fish store. The following tips aren’t the
ultimate answer, more a guide to give you and the Otos the best
chance for success.
Speak to the Workers at Your Pet
Ask them the following questions: How long they’ve had the
stock for? It’s common for Otos to die shortly after arriving
at a pet store, so if they’ve had them for a few weeks it’s
a good sign. What are you feeding
them? If they say ‘Flake food’ - say no and leave.
If they struggle to give you an answer - nope, this store is not
Take a Close Look at Their Appearance:
Check and see if they’ve got nice plump bellies, but, if
it looks bloated (like they’ve swallowed a marble), they
may have a bacterial infection. Look for good color: olive brown,
black and white. Avoid any with grayish white or bloody marks.
How do their fins look? In an ideal world, they’ll have
two sharp points on the edges. However, they’re often rounded
from stress or damage. Unless the damage is severe, don’t
worry too much.
Buy Tank-Bred Otos:
Easier said than done. Tank-bred Otos would be a better option,
expect it’s extremely hard to source. If you know anyone
- hook me up.
How to Introduce Your New Otos:
After you’ve selected the best Otos available, it’s
time to introduce them to your CYCLED aquarium (no measurable
ammonia or nitrites and nitrates are below 20ppm). You’ll
also want some algae growth in your tank for when they arrive.
BUT, before you take them anywhere near your tank, you need to
quarantine them for a few weeks. This will help confirm your Otos
are healthy and you’re not going to be introducing any nasty
diseases into your aquarium. Once you’re confident they’re
in good condition, you can begin to introduce them to their new
home. I recommend using an acclimation kit and drip method. If
you’re unfamiliar with the drip method. You can check out
this article here. Keep a close eye on them during the first month;
making sure you keep on top of your 25-30% water changes. If they
survive, you’ve got a big chance they’ll be around
for a long time - as long as you take care of them properly.