FAQs on Otocinclus
Related Articles: Otocinclus, Loricariids,
Related Catfish FAQs: Otocinclus 1, Otocinclus 2, & FAQs on: Otocinclus Identification, Otocinclus Behavior, Otocinclus Selection, Otocinclus Systems, Otocinclus Feeding, Otocinclus Health, Otocinclus Reproduction, &
Catfishes of South and Central America, Loricariid Identification, Loricariid Behavior, Loricariid Compatibility, Loricariid Selection, Loricariid Systems, Loricariid Feeding, Loricariid Reproduction, Loricariid Disease, Catfish: Identification, Behavior, Compatibility, Selection, Systems, Feeding, Disease, Reproduction, Algae
Social species... should be kept in a
shoal/group... Tropical... not cool/cold water... Freshwater
(Amazon), don't like salt/s.... or aggressive, fast moving
Albino Cory Catfish. Oto
I have a 30 gallon freshwater aquarium that has been well established
for over a year. All of my fish have been together since the beginning.
I just recently did a 75% water change and added new plants (water
changed due to long interval of no water change and new plants were
boiled for 15 minutes and rinsed with old aquarium water prior to
placement in the tank) I have tested my water with colored test strips,
everything appears to be perfect. I currently have in the tank the
following: 3 albino Cory, 2 zebra danio's, 14 neon's, 1 frog, 1
snail, and a monster of an algae eater (Otocinclus) that has become a
bit aggressive and very large. The problem is with my Albino Cory his
top or upper fin looks as though it has been nipped, he is well for
lack of a better word tipping.
<Mmm, the Oto...>
He can not seem to keep balanced in a stationary position like he use
to. Also, resilient as he is, he has started 'lodging' himself
against plants to stop from tipping. I can not say with 100% certainty
that he has been eating but he has been coming up for air like normal.
Also, I have noticed his breathing is much more labored than usual and
much more than my other two. What can I do I have had the Cory fish the
longest and do not want to lose him. Thanks for you help.
<I would move the Otocinclus elsewhere. Cheers, Bob Fenner>
Otocinclus with eyes missing
I just purchased four small Otocinclus catfish. While the salesperson
was catching them, she noticed that one was missing an eye and removed
him, commenting that "someone must have been picking on him".
I thought the others looked healthy but obviously I didn't look
closely enough. When I got them home, I noticed that two have an eye
missing, and one has no eyes at all. There is just a pale spot where
the eyes ought to be. The fish behave normally and don't seem to
have any trouble locating food. Do you think this is an injury-- some
vicious eye-eating tankmate? Or a disease?
What do you recommend we do? Thanks for your help!
<Hello Jan. The good news is that the loss of an eye seems to cause
most fish no problems at all. Eyesight is a far less important sense to
fish than it is to humans, even though most fish have excellent
eyesight. So a one-eyed fish can be bought and enjoyed with confidence.
Otocinclus, being catfish, have excellent senses including smell and
touch thanks to their barbels, and I'd expect even a no-eyed
individual might do okay, though it would probably benefit from being
kept alone for a while and getting offered its own food, such as algae
wafers. If it looked skinny -- something Otocinclus are prone to anyway
-- and failed to put on weight even with good care, then euthanasia
might be appropriate. As for why the fish has lost an eye, that's
usually fighting between fish in the tank.
Dwarf cichlids for example will attack small catfish and bite out their
eyes, something many casual aquarists don't realise. Failed
predation attempts, pop-eye, and rough handling by the fishkeeper can
also cause damage to the eyes, and once damaged, infected eyes often
fail to recover and simply fall off. There's no treatment as such,
and provided the fish can feed normally, one-eyed fish usually live
long and happy lives. Cheers, Neale.>
Otocinclus.. sys., comp., beh.
My name is Jessica, thank you for your help in advance. I have been
keeping Goldfish ever since I got my first ten gallon aquarium at the
age of nine.
For the past two years, I have had a 29 gallon freshwater planted tank,
which is also home to one brand new, week old, two inch Fantail
Goldfish and two Otocinclus.
<Mmm... not really compatible fishes... like very different water
The tank parameters are as follows, pH 6.4,
<Low for Goldfish>
Nitrites 0, Nitrates 20ppm or less,
<I would not let the NO3 concentration get any higher than this
Ammonia 0, and temp 70-72F. I do a weekly 25-50% water change and
vacuum the gravel at the same time while tending the plants. It is well
water so I don't need to add a dechlorinator. I bought the two
Otocinclus about two months ago and they have done an amazing job
cleaning up the algae in the tank. At the time the aquarium was home to
an eight inch, five year old Bubble Eye Goldfish who has since passed
on. His one eye bubble got so big that he kept catching it in his
mouth. It became irritated and in the 24 hours that I was not there it
managed to become infected and swollen. I placed him in the hospital
tank and gave him antibiotics but sadly his eye popped and he died two
days later. Since then I have been substituting the Otocinclus's
algae diet with some zucchini and spirulina wafers and have left the
back and sides of the tank alone for them to clean. When I first got
them they both had Ich and one of them had almost its entire caudal fin
missing. Unfortunately, I read that this was rather commonplace during
the shipping process.
<This is so>
Anyway, its fin has regrown and they both seem to be doing fine. What
concerns me is that their dorsal fins always seems to be held tight
against their bodies, they have been this way since I got them, is this
just normal behavior for them?
<Mmm, yes. A general statement re freshwater fishes is that their
fins are "down" for most of the time, vs. marine fishes,
whose fins are "up" most of the time>
They seem happy otherwise zooming around the tank and they really love
their zucchini, although the new goldfish is fighting them for it.
Also, I was thinking of raising the pH just a little bit, up to 6.8,
and to this end was thinking of boiling some shells, cracking them, and
placing them in a glass bottle in the tank.
That way the fish could not get cut on them and they would be easy to
take out if the pH got too high. Do you think this is a good idea or
would you recommend to just leave the pH alone as is?
<I might instead add a bit of sodium bicarbonate (baking soda) to a
given batch of make-up water (in storage and tested ahead of use) to
get a proportion of how much you'd be adding to raise the pH on a
regular basis... but the shells are again a good/safe source. Bob
Oto question, sys., comp., repro.
Here's a little background.
My wife and I recently setup a new 10 gallon tank.
<A small tank; not recommended for community tanks.
We got an internal filter. We use a heater (which raises the temp by 4
degrees), the temp is usually 73*F without the heater, but based on the
fish we had, I thought 77*F would be a better temperature,
<Does depend on the fish.>
and our heater doesn't have a setting (other than on or off). For
now we leave it plugged in and achieve 77*F. We started with 2 Neon
Tetras, 3 Black Mollies, and 1 Otocinclus.
<72-75 is ideal for Neons and Otocinclus, but tank-bred, fancy
Mollies really need slightly warmer conditions, 77-82 F.>
One of the Neons died within 24 hours. The other neon became so lonely,
it stopped playing in the bubbles, it stopped eating, and died of
loneliness within a week (even the mollies wouldn't play with it
when it tried).
<Let's step away from ideas of "playing" and
"loneliness". Neon Tetras are difficult to keep unless you
have cool, soft water. You're aiming for pH 6-7.5, 3-10 degrees dH.
They won't do well in the hard water Mollies MUST have to stay
alive. So these two species are NOT compatible. Neons also need to be
kept in groups of 6 or more.>
We added 2 more Black Mollies, all these fish so far have come from
<Mollies really won't do well in 10 gallons of water. The males
are aggressive towards each other and the females. They are also very
sensitive to poor water quality, making them bad choices for new tanks.
Do read here:
After a few more visits to PetSmart, we noticed that some of their fish
had Ick. We then noticed ours did too. We tried 2 treatments (1 and
then another 24 hours later as per the directions) of a bubbling type
tablet that was supposed to clear the Ick.
<Hmm'¦ with Mollies, your best bet is the salt/heat
It removed smaller spots of the Ick, but the Mollies still had large
amounts on them. Unfortunately we couldn't afford the treatment
when we first noticed it.
<Salt is cheap, so not treating fish for Ick shouldn't ever be
an issue. While aquarium salt is ideal, any non-iodized salt should
work fine as well.>
I think we noticed it on a Tuesday, and we bought the treatment on
Saturday and started administering it Saturday evening. One of the
female Black Mollies died the Friday before we got the treatment on
Saturday. So, by Saturday, we had 2 males and 2 females (Black
Mollies). We still had our 1 Oto (I believe female based on the fact it
immediately started going up and down the tank and across the tank
almost immediately after we got the heater to raise the temp to
<You can't sex Otocinclus this way.>
Websites also suggest this is the perfect temp for breeding Otos. (I
had no idea).
<Actually, Otocinclus should be kept fairly cool. They are extremely
sensitive to low oxygen concentrations, and as you hopefully remember
from school, the warmer water gets, the less oxygen it holds.>
As a side note, we also have lots of snails, and they have been
fruitful and multiplied. We started with 1 Black Mystery Snail (fully
grown) and about 12 baby snails (golden and black mystery mostly). Long
story, but we were wanting 2 or 3 babies, but we ended up with about a
dozen of them. Most of the baby snails died off (presumably
<Actually, Apple/Mystery snails do bad in aquaria. Don't keep
them with fish.>
Before we knew it, there were little specs above the water line. Our 2
airstones were moving water rather violently at the surface, and the
filter sucks in water, then pours it onto the surface. This was perfect
for the snails as they could put their eggs above the waterline and
they would constantly be wet by the popping bubbles. I suspect the Otos
also enjoyed the constant streams of current as well. By the way, I am
sinking every snail egg I find right now. Well, most aquarists would
have suggested that a new tank is the least likely scenario for fish to
breed. Not only did the snails breed, but the Black Mollies bred.
<As is their wont.>
One day I found a little fry at the bottom. I about had a heart attack
since I never even knew the Mollies were thinking of reproducing.
<I think "thinking" is over-egging the pudding a bit.
Males will inseminate anything vaguely Molly-like, and do so
persistently. In a 10 gallon tank, the females get stressed and often
miscarry, which you can recognise because miscarried babies are either
stillborn or so weak they fall to the bottom of the tank. Healthy
newborn Mollies can swim immediately after they are born, and
instinctively hide among floating plants *at the top* of the
I went to bed and prayed that it would survive.
<Prayer has it's place, I'm sure, but there are some more
immediate things you can do to keep Molly fry alive. Do read the above
By the next morning I wanted to save our little Molly and make it some
makeshift tank to keep it from being eaten. (Where there's a
redneck, there's a way). Keep in mind, that we are very financially
struck at this point.
<That's fine. Here's a tip: stick in some floating plants.
Floating Indian Fern is ideal, but even "goldfish weed" like
Brazilian Pondweed works well. The fry will hide there and won't be
eaten. Plus, floating plants give the female cover, and that reduces
the stress they get from amorous males.>
So, I found a casing that is used as a top to CD's. (if you go into
Wal-mart and state that you want to buy about 50 blank cd's You
will get a container that has a very large round lid. Since we still
had one of these containers, we simply took the lid off and turned it
upside down. It may not be large, but hey, it's what we can afford
for the little fry.
<Have done something similar myself. Use a screwdriver to punch a
few dozen small holes in the side so water can in and out, and so much
the better! If you don't do that, you'll need to change the
water in the container at least once a day.>
I went to find it and it was gone. I even moved the shell and gravel
around where it had been hiding the night before. We have about 12
large shells throughout the tank.
<Often what happens with very weak fry is they die, snails come into
the floating trap overnight, eat the carcass, and then the snails crawl
The gravel is a bit rough and not exactly ideal for fish tanks. I
feared it had been eaten. Several days later, we found one that looked
similar to it, hiding in the back. I believe it's the same one, my
<Molly broods can be anything up to 100 fry, though commonly
Either way, we caught it and put it in this makeshift tank I mentioned.
My wife got the idea that we should take one of the air stones out and
simply place it in the makeshift tank.
This seemed like a good idea at the time. I mentioned that it wont have
a filter or heater, but she doesn't have any idea how to solve
that. We put a shell in it too. The little fry loves to hide inside the
shell, or near the air stone. After trying to look through my daughters
binoculars backwards, I did see it fan its underside fin out showing me
that it is a female, because the males have a longer pointy fin in that
<You can't sex Mollies at this age. The males won't develop
their gonopodium until they're about 2 months old. Until then, they
look just like females.>
It is still too young to know for sure, but I believe it is a girl. So,
now back to the Otos, which is what I am really interested in. Since
the one Oto was trying to attract a mate, and there wasn't one, we
bought 2 more Otos.
<Not trying to attract a mate, trust me. These are SCHOOLING fish
and want companions.>
PetSmart didn't have any and hasn't in the few weeks since we
had bought the first one (the only one they had at the time). We had to
go all the way to Norman Oklahoma from Bethany Oklahoma just to get
Otos that day.
<I assume that's a long way'¦?>
None of the PetSmart stores has any in the greater Oklahoma City area.
So we went to "Wet Pets by Steve" in Norman, Oklahoma. We
bought 2 Otos (I wanted at least 1 male). When we looked at the Otos, I
was unsure how to tell the sexual differences in Otos (I just had some
very generic ideas from what I had read online).
<You can't sex them. Mature females become fatter when filled
with eggs, but that assumes they're sexually mature and
"conditioned". Specimens in pet stores won't have eaten
properly for weeks, so the chances of the females being ripe with eggs
are next to zero.>
The gist of the online info was that males are smaller and thinner. The
females are larger and potentially rounder. I noticed 1 Oto that was
certainly different that the one we had. If you could imagine a line
between the Otos eyes, and draw a triangle to its tail, that is what
our original Oto looked like. But this one was different, the triangle
only went down about half way down its body, then narrowed severely. It
was almost like it got pinched on the hind end. I figured this meant it
was a male, and the ones I am calling triangular are female. The little
guy was very active. We bought it, and another one that I believed was
female. I figured that if I bought 2 different ones, there would
definitely be at least 1 male and female in the tank.
<Actually, you need to get at least six of them for Otocinclus to be
happy. Forget about males and females. You can't sex them.>
When we acclimated them to the tank, I noticed that they were a lighter
color, they were smaller, and my wife noticed that our original Oto has
<More than one species in the trade: Otocinclus affinis and
Otocinclus vittatus are the commonest.>
The three of them do hang out quite often, but the one I believe is
male, is favoring the new female (not the original). None of them are
doing the chase and follow routine. I read online that Chinese Algae
Eaters are sometimes mistaken for Otos.
<You'd have to be legally blind to confuse Chinese Algae Eaters
with Otocinclus! They are completely different. Otocinclus are much
smaller, 1.5-2 inches, tops, Otocinclus affinis is grey above with a
thick black region along the midline of its body from nose to tail, and
off-white below. Otocinclus vittatus is essentially grey above, darker
grey along the flanks, with a thin pale band between these two grey
regions, and then off-white below. The Chinese Algae Eater
(Gyrinocheilus aymonieri) is more or less green all over with a few
bluey-green patches along the top surface and a distinctive zig-zag
bluey-green stripe along the midline. The Chinese Algae Eater is big,
fast-growing fish that gets to about 8 inches within the first year and
around 12 inches within the second. It is notoriously aggressive and
has no place in a community tank.>
I am hoping that we have 3 Otos. The littlest one (the one I believe is
male) is not afraid of the Black Mollies (as the others will get out of
the Black Mollies way when picked on). In fact, it even seemed to
attack the Black Molly who bothers it. This seemed very strange to me
for a tiny fish to stand up to and even fight back against a much
larger fish. The Black Mollies have learned to leave it alone.
<Hungry Otocinclus have a bad habit of rasping at the bodies of
other fish. They scrape at the body eating the mucous, but in the
process they create nasty wounds. Some fish learn to avoid them, which
could easily explain why the Molly seems nervous around them.>
The 2 new Otos are about an inch long (or slightly less). I believe our
original Oto is full grown, but still short of 2 inches (I have no easy
way to estimate its size). So, now on to the good stuff. Long before we
added the new Otos, I had performed a 50% water change. In the process,
we noticed a clear gel on the back of the filter. Not knowing what it
was, we tossed it out. I later, realized it might be Oto eggs. The
snails are all mystery snails and lay their eggs above the water line.
The Black Mollies are live bearers. The Neon Tetras died before even
the idea of multiplying. So by process of elimination, I figured the
gel had to be Oto eggs.
<Likely snail eggs.>
A quick reference on the internet confirmed this is a very likely
scenario. I eventually noticed 3 new areas of these egg gels. 1 of the
gels got scraped while trying to catch the Molly fry. I eventually
scraped the rest of it off the side of the tank where it was and let it
fall to the bottom. It seems I am finding several of these egg gels
now. I am concerned that our tiny male may not even be an adult yet
(and that our 2 females may have to continue to be "ladies in
waiting"). I noticed one of the group gels just disappear.
<They're snail eggs, likely from Physa or Physella spp. snails.
Even if you haven't seen them, they're in there. Fish eggs do
not look like clumps of jelly.>
It was truly strange, when my daughters came to visit, I clearly
pointed the new gel out and about 2 hours later, the gel was gone. I
suspect a molly ate it. That is one of my questions (Will Black Mollies
eat Oto eggs?). Next, some of them look ripped, as if something cut
them in half. Does this rip mean they hatched ?
<Sure, the snails hatch out within a few days.>
Could a snail have accidentally ripped it when it went over this gel ?
The snails are about the same size, or maybe slightly larger. I have
kept a pretty detailed "fish log" and it's kind of like a
diary of my observations in the tank. Apparently we started the tank
08/07/10 and added fish on 08/08/10. One phrase I used in my fish log
(after discovering the Black Mollies like algae tablets and algae on
the side of the tank and decorations) is "An Army of Algae
Eaters". Yep, every single fish in the tank loves algae. Could be
a reason why they thrive when using the 60 watt bulb until it burned
out and changed to a 100 watt bulb.
<You're using incandescent bulbs? I would not recommend this.
For a start, they're useless for growing plants, and they also
waste a lot of electricity. But they're also dangerous -- splashing
water on hot bulbs = explosion! If your hood has sockets for
incandescent bulbs, I'd STRONGLY suggest replacing the bulb with a
much cooler and less wasteful compact fluorescent
I was uneasy with the idea of causing that much algae. We still could
see green areas forming on the glass, but our army usually did a pretty
well job of cleaning it but couldn't clean it fast enough. We now
have a 15 watt bulb. I am concerned how much algae I need to
<Otocinclus starve quite easily; if they look "hollow
bellied", i.e., their bellies are concave, they're starving.
Algae wafers are good, but so is blanched lettuce, squished cooked
peas, sliced cucumber, sliced zucchini and cooked spinach.>
I dropped algae tablets in the tank and our original Oto never had any
thing to do with them. Our Black Mollies loved them. Once we added the
2 new Otos, I tried it again and they (the 2 new Otos) love the algae
tablets. So my biggest questions are concerning the Oto eggs. How do we
know if they were fertilized ?
<Snail sex is complicated. They're usually hermaphrodites. Some
species also have all sorts of fun stuff with 'love darts' well
worth reading about.>
How can we know if they are hatched (or damaged). Are the Oto fry good
enough at hiding for us to remove them before they get eaten ? And for
the strangest question of all.... would it be a bad idea to move some
of the Oto eggs to the tank the Black Molly fry is in ? Would she eat
the eggs ? Would she eat the fry ? She is still very small (I'm
guessing about 1 centimeter long). And finally How many Oto fry hatch
from an egg gel ? The gels themselves vary in size as it is. My wife
suggested that the gels might be mold. But they are clear.
<They're snail eggs!>
They look like they have white bubble specs in them. If we should try
to setup a third makeshift tank, how important is it going to be to
have a heater, filter, or airstone ? I'm sure they are Oto eggs
because as a test I ran room temperature water over our largest
ornament (a ceramic angel where the Otos love to hang out), and shortly
later there was an egg gel near the angel. The pictures I could find
online of Oto eggs are of 1 to 4 eggs and not a gel. I searched your
site, and nothing quite seems to cover these scenarios. But then again,
I may be a redneck, and things are always a bit different with
<Are they? Forgive this ignorant Englishman not really having a clue
what you're talking about.>
So, to make things clear, we now have 4 Black Molly adults (2 female
and 2 male), 3 Otos (I believe 2 females and 1 male), and several small
snails (the largest one died). In retrospect, maybe the little Oto was
protecting eggs I hadn't even noticed yet ? I sure hope it's
not a Chinese Algae Eater. I appreciate any and all help you can give
<I hope this helps. Cheers, Neale.>
FW Parasite problems (RMF?)<<>>
Dear Crew Member
I have several niggling health/parasite problems in my freshwater
aquarium. I have done much reading, much sifting through the WWM FAQs
and related articles, but I fear that now the information I have
gathered is beginning to diverge rather than converge, and was hoping
that you might be able to provide guidance on my next steps.
I would like to begin by defending the tank itself. It is a sumped,
280L (73 US Gal) planted tank with soil underlayers in both the display
and sump. The lights are timed so that when the main tank is dark, the
sump is lit. Plant growth is excellent, and no fertilisers are added
(as per Walstad doctrine). I have never (yes never) registered any
ammonia, nitrite or nitrate in this heavily planted tank, and pH is
steady at 7.5. General Hardness is 4, while KH is the only thing that
fluctuates a bit between 4 and 6. Apart from the problems that I will
list, the fish are vibrant and feed well. In fact I have never seen
them so 'happy'. But:
<Sounds a good tank so far.>
My main concern is an aged Bolivian ram. I acquired this fish when it
was fully grown a year ago. Its symptoms are flashing (focusing on the
gill area), darting, shimmying, and flecks on its eyes. Sometimes its
skin looks a little shredded -- white lines from the back of the head
along the flank, as if it has been cat-scratched. But then this last
symptom will suddenly disappear, the flashing will calm down and I am
tempted to think that it has got over whatever problems it has. Except
<Right. Now, ruling out water quality issues (by far the most common
reason for chronic, low-level health problems with nebulous symptoms)
the things to consider are toxins, diet, stress and some type of
non-lethal parasite. Toxins could be things like paint fumes. Not a
common problem, but possible if the tank is near a workshop or garage.
Diet is generally not a major cause of problems with small community
fish, but dried foods do lose their nutritional value once opened, so
some care needs to be taken here. Stress can include behavioural
interactions. For example, one time I kept some large freshwater gobies
and had no idea why they constantly exhibited sores on their flanks.
Then I noticed the Otocinclus feeding on the mucous on these fish. One
thing many aquarists don't know is that Otocinclus are
semi-parasitic and view large fish as moving buffets, and if hungry
will scratch away at such fish, causing inflammations and excess mucous
production. Finally, there are mystery parasites. Farmed fish generally
come with predictable parasites such as Ick and Camallanus worms that
are common in fish farms and in tropical fish shops. But wild fish can
and likely often do come with low-level infections of non-lethal
parasites that we don't notice and so don't treat.>
Concern number two is the five Corydoras sterbai in the tank. They will
flash against the substrate.
<Typically implies irritation of the gills, e.g., by ammonia or
These were new fish added in the second month of the tank. One of them
has always had a white dusting on each flank (which I didn't notice
in the shop), and a stumpy, Nemo-esque pectoral.
This dusting is not Ich, and does not seem to change or shift. But they
are all feeding and growing well and otherwise happy.
<Possible velvet; would at least treat assuming it was, since no
harm will be done. Salt works well here. See here:
Problem number three is a very old Otocinclus that occasionally
'furs-up'. Every two months or so it looks as if it is in the
last stages of a fatal illness -- and then the next day any sign of it
has completely gone. Perhaps some sort of mucous excretion here?
<If the "fur" is off-white to grey slime rather than
fluffy, then sure, could be mucous. Commonly caused by what we usually
call Costia, or Slime Disease.>
The other three Otocinclus are fine, fat and have grown very well.
Problem four is my shoal of cardinal tetras. They have been with me for
over two years now, but currently seem to have some sort of grey-white
bean-shaped (like a tiny grain of rice) parasite that sits vertically
on their flanks. They flash now and again, presumably to try and
dislodge whatever these things are. The suspected oldest fish of this
shoal is the worst affected.
<Without a photo, it's difficult to say. Could be a Fish
Pox/Lymphocystis type thing, and in itself not fatal but a sign of some
environmental stress.><<More likely embedded Microsporidean
colonies... common, not treatable as far as I know>>
(Might age be a theme here? The ram, the Oto, the original tetras -
could this point to dietary deficiency? I feed frozen, recently opened
flake food, and crushed algae and cichlid pellets.)
It is a similar case with the marginatus Pencilfish that I acquired
(about the same time as the C. sterbai) -- the same tiny flattened
rice/bean on their flanks, almost as if they have swapped one of their
scales for a discoloured one. Could they have in fact lost scales for
some reason from an invisible parasite, rather than the mystery bean
shape being the parasite itself?
Other inhabitants that are unaffected are 2 glass blood-fin tetras, 10
Boraras brigittae and 1 female Apistogramma trifasciata. The tank is
also home to 2 Nerite snails, Malaysian trumpet snails, 'small pond
snails', Amano shrimp, cherry shrimp, and other unidentified
<All these invertebrates will likely be killed by copper-based
medications, so be careful how you treat the tank.>
I must point out that the ram, the cardinals and the blood-fins had a
similar parasite in a previous incarnation of this tank. When I added
the sump, I was able to isolate them, cook them at 30'C and treat
heavily with copper. Whatever it was appeared to clear completely.
<Good. However, do consider that moving them to another tank was the
cure, rather than the copper. If the Otocinclus are attacking other
fish, then separating them will help the victims heal. If there's a
toxin of some sort in the display tank, the hospital tank can provide
relief. In other words, be open minded.>
However, all plants were transferred to the new tank (despite sitting
in a bucket for a week with a double dose of copper treatment), as were
the shrimp, who spent time in a separate tank with the micro-Rasboras
(who appear completely immune to whatever this is). Perhaps this
parasite survived either via the plants, or the shrimp. Problems
started again before the micro-Rasboras were added, so they can be
excluded as the main cause.
I must state that I do not believe this to be a water quality or
husbandry fault (apart from a lack of quarantine on my part, mistakes
in transference etc). To repeat, I have never tested anything amiss in
this tank, and all species should be fine within the water parameters,
and with each other. There is no overt aggression in the tank. I think
I introduced new pathogens either by not quarantining new stock (which
I certainly will in future), or letting old ones ride in on the shrimp
(or in the shrimp).
<Shrimps won't carry parasites as such, but any wet object,
including shrimps, can carry the free-living stages for a period of
time, perhaps a day or so.>
So unfortunately these parasites are there now -- but can you help me
ascertain what they are and recommend a course of action? Already I
have raised the temperature to 29'C (84'F) and have added a UV
sterilizer, although this does not appear to have made a significant
<It won't. UV is good at reducing the prevalence of free-living
parasites, but by itself it's almost never the cure.>
From my research so far I'm thinking that it could be Costia,
Chilodinella, Icthyobodo or some sort of fluke, or a combination of
these -- but quite honestly I don't have a clue.
<Costia (= Icthyobodo) is a good guess for "slime disease"
I have not yet added a treatment, as most of them look to be
shrimp-killers, and to be frank, apart from a bit of flashing, the fish
have been generally fine. But obviously I wish to eliminate the
pathogens from the system, and the ram's discomfort is evident
enough to now be worrying.
In terms of stages I would like to 1) try temperature raising to
30'C and UV sterilization
<Warming the water can speed up the life cycle, but it can also
stress certain fish, so balance the two things.>
2) perhaps (although I'm not keen) try adding salt (would this help
if it were flukes? -- opinion seems divided)
<Salt is a low-risk approach for treating Velvet and Ick. To treat
Costia requires high salinity dips and a somewhat higher salinity in
the tank, so while low risk in itself, it has to be done properly. Salt
water dips can help treat flukes. Do read here:
3) trying a shrimp-friendly anti-parasite medication (Praziquantel --
if I can get hold of it here in the UK)
<Yes, you can get this from a vet. I would treat the fish in a
hospital tank and leave the tank fallow for a while. Alternatively,
keep at least some shrimps and snails in their own tank in case the
ones exposed don't survive.>
and finally the last resort of 4) resorting to a formalin and
<The nuclear option!><<I would NOT do this>>
Other options I have considered are moving the shrimp to a spare 40L
tank and treating the main tank. However, what would I do with the
<Once isolated for a few days, shrimps shouldn't carry any
viable fish parasites at all, provided they really are isolated. That
means taking care not to mix nets, buckets or anything else that could
bring more free-living parasite stages into the shrimp tank. Do review
the literature here at WWM re: treating marine whitespot in reef tanks;
essentially you're doing the same thing here.>
How long would they have to be in isolation to be guaranteed parasite
<In theory things like Ick can live without a fish host for a day or
two, but in practise you want to leave the tank fallow for a couple of
weeks at least. Again, refer to the marine articles on this
Alternatively, do I cram all the fish (if I can catch them - Sheesh I
do not look forward to that afternoon) in the 40L, blitz them with
heavy meds and leave the main tank and shrimp fallow?
<Could work, though 40 litres would be a bit tight. Try using 5
gallon buckets with lids if you need extra "tanks". If you
add a heater and filter of some sort, these can work fine for a
Would this work or will the pathogens hide in the substrate?
<They can't hide indefinitely, and there really is an expiration
date of sorts on the free living stages of most parasites.>
This tank will one day become a reef tank, so avoidance of copper in it
would be preferable.
Any insight you can offer would be much appreciated.
<Hope this helps.>
I apologise for the length of this query. Let me finish by saying that
WWM is by far the number one web resource I know of for problem solving
- I have used it to research two unrelated issues already, with
excellent results. Your generosity with time and information is, quite
frankly, no less than a credit to humanity! So big thanks.
<Kind words indeed. Cheers, Neale.>
Re: Parasite problems (RMF?) -- 3/31/10
Thank you for your excellent, attentive response. I am enlightened on
several issues, and corrected on my diseases! I hope you don't mind
me coming back at you with a couple of points/queries.
Firstly, I've read your article on salt use, and I will give it a
try, on the basis of treating velvet. For optimisation, I assume I keep
the UV sterilizer on at this stage?
Secondly, I did not know that Otos could go that way. I have not
observed this behaviour (despite occasionally observing the tank at
night with my rear bike-light), but will remain vigilant. When this
condition was previously 'cleared' the Otos were in the same
tank as everyone else - so I think they might have an alibi on this
<Not saying the two things are connected, but I wouldn't trust
Otocinclus, period, and that's based on witnessing the havoc they
Thirdly, I am sorry to say that today I noticed that both the Apisto
and the blood-fins have now started flashing. I am certain that they
try and scratch their gills. All of them - they are all trying to
scratch their gills - it is gills, gills, gills - this I would strongly
bet on. So from what you wrote I would assume that you would think this
is indicative of either a) ammonia b) a toxin or c) velvet?
<You can't tell which of these. So has to be a process of
elimination. Test for ammonia; consider possible toxins; treat for
I feel confident I can discount ammonia - as soon as a problem arises
my tests kits get used - sometimes several times a day, sometimes late
at night. I use different test-kits, and have the water tested at
different fish shops. Never anything amiss.
Regarding toxins, I (and my family) are very careful around the tank,
concerning cleaning products etc. I would have thought that if there
was a toxin in there, all fish would be immediately irritated, rather
than this progression of irritation, that is currently leaving the
<Yes and no. For example, air-breathing fish (like Corydoras) are
going to be more sensitive to airborne pollutants than other types of
fish. Then again, some fish are intrinsically more resistant to poisons
To give a textbook example, among marine fish Opsanus tau is famous for
being able to live and breed in harbours where virtually everything
else has gone. So there are shades of grey here.>
When I added the fish back to the tank (after their stay in a holding
tank where they were treated) there was no sign of any flashing for a
few weeks - possibly even nothing before I added the C. sterbai. Is
there any other avenues I could pursue to discount a toxin being a
<Could be air, could be errant children (not to be ignored, this,
how I lost my first goldfish as a boy), and also things in the tap
water, e.g., chloramine if not treated for, or copper, if not treated
I worry there isn't. As a long shot, could smoking (in the garden)
and then feeding fish somehow put toxins into the water?
<Can't see how.>
But again I would expect a non-gradual progression of irritation -
blanket irritation if you will, rather than this flashing behaviour
moving slowly from fish to fish. What do you think on this
<Yes, it's what you'd expect. But the thing with biology --
as opposed to the other sciences -- is that there are always
So I will try the salt approach at 2g/l. While I have you Neale - this
is probably a no-brainer, but do I go with cheap table salt, or should
I give them some Maldon?
<If using salt from the grocery store, then I would use, and have
used, rock sea salt or better still kosher salt (which doesn't have
any additives at all). But ideally, use aquarium/tonic salt -- not
marine salt mix. The cost difference will be trivial, and perhaps worth
it for peace of mind.>
Tiger barbs and Otocinclus I just brought home 3 Otocinclus
and 1 twig catfish for my 29 gallon tank containing 4 tiger
barbs. The tigers are ganging up on the Otos and chasing
them all over the tank. I am worried that the stress will
kill them! They have not spotted the twig cat yet but I have
just read that the twig cat is easily harassed. These are
the fish that were recommended by the aquarium store (Old Orchard
Aquarium in Skokie, Illinois) knowing that I have the
barbs. I was going to buy a clown Pleco having read up on
them. The guy in the store said they were not good algae
eaters and to get the twig cat instead. I am
ticked! I don't want these fish to suffer but what if
the store won't take them back tomorrow? <Hello, Tiger Barbs
sure can be terrors. If you provide plenty of cover and dark
hiding places they should be ok. Live plants are
great. If the tiger barbs do not ease up on them after a
while you may want to consider removing the
Otocinclus. Please be sure that there is enough food to go
around for the Otos and the twig catfish. Have you checked
out the article below, good stuff. Best
Regards, Gage http://www.wetwebmedia.com/FWSubWebIndex/otocinclusart.htm>Otocinclus
I just got a little Otocinclus which I planned to put in my 25 gallon
aquarium. The aquarium has 2 goldfish, one a solid 5 inches long and
the other smaller, maybe 4 inches long but most of which is a fan tail.
I put the little Oto in, and got quite worried that they might eat him.
This morning I found him in an impossibly small corner, just barely
under water, where they could not get him. My question is,
should I take him out and keep him elsewhere until he is larger or will
this always be an issue. Alternatively, will he be a good hider and I
will be able to stop worrying. <The Oto really isn't a good fish
to go in with Goldfish. The goldfish like cooler temps than the Oto and
the Oto stays small enough that him getting eaten is always going to be
a concern. Your best bet is going to be to put the Oto in a separate
tank or return him to the store.> Also, the pet store said that one
Oto would be fine, but I read this morning that they should be kept in
groups. What is your advice? Thanks! Carol <They are much happier if
kept in groups. Ronni>
Firemouth Bit Off More Than He Could Chew I tried throwing
some Oto's to clean up in my cichlid tank. A few days, all was
well, but yesterday morning I see a tail sticking out of my
Firemouth's mouth. Nothing I hadn't seen before, except that
the tail end was still sticking out last night, and this morning as
well. I just got home from work and he still hasn't been able to
swallow it down. I thought of netting the Firemouth and trying to pull
it out, but I figure that I can end up tearing up his throat. He
doesn't seem overly stressed about it, and has even kept up his
harassment of a larger jack Dempsey in the tank. I believe he was even
eating some of the flakes I threw in earlier. Having been at least 36
hours, what should I do? Keep waiting and hope he eventually gets it
down, or try and pull it out even though I may do a lot of damage?
Anyone else have this kind of problem before? < Unfortunately,
Oto's like most catfish have stiff spines that they use for
protection from predators. I would take him out and get a good look at
the mouth. I would be tempted to take a pair of small scissors and cut
the spines on the Oto and extract the body. Then use tweezers to
extract the spines. If you can't pull them out then I would push
them through and pull them out from the other side. Not often but it
Otocinclus question ... plants/comp.
3/18/06 I have several Otocinclus catfishes in a 46 gallon
freshwater tank with 2 Gouramis, a couple of tiger barbs and 2 clown
loaches. Just last weekend I purchased several nice Amazon
plants and to my dismay they seem to be getting little holes in the
leaves, about the size of the Otocinclus' mouths! <Ah, yes>
Could they be the culprits, I haven't seen any other of
the fish hanging around the plants? <Could be... but also the barbs,
loaches... however the Otos are most likely at play here> I found
reference to them needing plants around but I wasn't sure if that
was for hiding places or to eat. <Mmm, both and more. Bob Fenner>
Otocinclus and Comet DON'T MIX! EMERGENCY
07/21/06 Hi, love your website, thanks for it, but I have
a huge problem!! <<Hi, back. You're welcome.
Let's see what we can do. (Tom here, by the way.)>> I woke up
today to find my Comet munching on my Otocinclus! Actually, what I mean
by that is that the Oto was lodged in his mouth with about 25% of it
sticking out. He doesn't appear to be choking because he is still
breathing. <<I assume you're referring to the Comet because
the Oto doesn't sound to be in good shape.>> I got two new
Oto's a couple days ago and since then they've both been
lethargic with clamped fins, each was tiny, 1 inched guys and my Comet
(Harry, don't ask) is about 4 inches long excluding his tail.
He's always been greedy and I think what happened is
the Oto died and the Comet finally could catch him and did. <<Not
unusual for Goldfish to do this. They tend to be
"opportunistic" feeders and your Oto gave Harry the chance he
was waiting for...unfortunately.>> No search engines helped me at
all! <<In fairness, it's not the typical inquiry.>> At
this point, Harry is moving slowly and keeps sucking or blowing his
mouth, I can't tell which. This is a major problem and one way or
another might solve itself before you answer back, but right now my
main concern is lack of ability to eat or transfer air in the swim
bladder, and of course lodging it in more and choking! <<As long
as he's moving water over his gills, he's not
"choking". He may not be very comfortable but he won't
suffocate.>> Just in case he lives and for future references
please help! I tried using metal tongs and I grabbed the protruding
tail but I couldn't get it out, I'm sort of nervous of pulling
too hard. How do I dislodge it, or can he digest the head soon enough
and eventually pass it through?? (I seriously doubt it though.)
<<I seriously doubt it, too. Goldfish are primarily
"vegetarians". Their systems aren't developed for dining
on other fish. Likely the dorsal rays are getting caught in Harry's
mouth as you try to pull the demised Oto out. You might try twisting
the Oto one way, or another, to get the rays to
"release".>> And should I remove my other Otocinclus
and my (very lively and quick) Algae eater? <<First, if by
"Algae Eater", you're referring to a common Plecostomus,
I wouldn't worry about this. Harry isn't likely to be
interested in a "lively and quick" tankmate. My concern here,
without getting on a soapbox, is that many Otos are
"captured" in the wild by the use of cyanide. I have no
direct knowledge of these fish being bred in farms, though it's
entirely possible that they are. In any event, the fact that both of
yours showed signs of lethargy and clamped fins indicates, to me, that
it's possible that they were taken with cyanide, a chemical that
will, unfortunately, stay in their systems. Otos, regretfully, show an
inordinate amount of "infant mortality", meaning that they
often die within hours, or days, of being introduced into the tank.
Fish that feed on the dead fish are going to be ingesting cyanide if
the deceased fish contain this in their bodies. My recommendation is to
get the Oto out of Harry's mouth regardless of what it takes and
remove the other Oto from the tank. Easier said than done, I know, but
you must do this.>> Thank you for your time, and sorry my email
is so long. This is my first major goldfish problem and I'm very
anxious. <<Not to worry. You're more than welcome and I
completely understand. Tom>>