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FAQs on Otocinclus Health

Related Articles: Otocinclus, Loricariids,

Related Catfish FAQs: Otocinclus 1, Otocinclus 2, & FAQs on: Otocinclus Identification, Otocinclus Behavior, Otocinclus Compatibility, Otocinclus Selection, Otocinclus Systems, Otocinclus Feeding, Otocinclus Reproduction, & Suckermouth 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 Eaters,

Otocinclus anatomy or parasite? /RMF      1/19/19
Hi Crew! All has been well in my tanks and I hope the same is true for you.
I've got a question for you about Otocinclus that I wonder if you can help me with. Despite having been previously wormed, and in my tank for over a year, I saw something suspicious protruding from the vent of one of my Otocinclus. I immediately suspected tapeworms and have searched with Google to see if I could find what that would look like. I found a couple of images (I will add the links) and a YouTube video showing Otos with a similar feature so now I'm not sure if it is actually a worm or a normal body part. I haven't been able to get a picture of my actual Otocinclus but the linked images are pretty much the same as what I saw with mine.
<Does look like something "worm-like" is protruding from the fish's vent>
These pictures were from a forums post wondering the same thing as me, whether it's a worm or tapeworm segment or an anatomical feature, unfortunately they never found an answer.
This picture was posted without comment so the person who had this fish didn't think there was a problem.
So is this a normal thing, some kind of breeding apparatus maybe? Or is this an unwanted passenger?
<Could be... a Nematode...>
Otos are reclusive enough in my tank that I don't really know what's normal or not, 7 of them disappear in a 450lt tank. Hopefully you can point me in the right direction! I do have dewormers available (both Praziquantel and Levamisole) if necessary although I don't relish the idea of dosing a tank of that size. The tank has loaches and Corydoras in it as well so if there is tapeworm or otherwise present I would expect it would have spread to them too by now.
So far I have one rotund Oto and some of my loaches that I had thought were full of eggs too, but now I'm concerned for worms. On the other hand, I haven't seen any symptoms in any of the other fish (rainbows, gudgeons, tetras).
<I wouldn't try/treat these Otos... likely this is either not a parasite, or if so, not debilitating... enough to warrant vermicide use>
Thanks for all your help over the years, sometimes it's just not possible to Google an answer for something (not a lot of people have taken detailed pictures of their Oto's vents!).
Bronwen @ Australia
<And you, Bob Fenner in Calif.>
Otocinclus anatomy or parasite? /Neale      1/19/19

Hi Crew! All has been well in my tanks and I hope the same is true for you.
I've got a question for you about Otocinclus that I wonder if you can help me with. Despite having been previously wormed, and in my tank for over a year, I saw something suspicious protruding from the vent of one of my Otocinclus.
<The standard de-wormer, Praziquantel, isn't especially effective. It's worth doing several rounds. Flubendazole and Fenbendazole are generally more reliable than either Praziquantel or Levamisole.>
I immediately suspected tapeworms and have searched with Google to see if I could find what that would look like. I found a couple of images (I will add the links) and a YouTube video showing Otos with a similar feature so now I'm not sure if it is actually a worm or a normal body part. I haven't been able to get a picture of my actual Otocinclus but the linked images are pretty much the same as what I saw with mine.
These pictures were from a forums post wondering the same thing as me, whether it's a worm or tapeworm segment or an anatomical feature, unfortunately they never found an answer.
This picture was posted without comment so the person who had this fish didn't think there was a problem.
So is this a normal thing, some kind of breeding apparatus maybe? Or is this an unwanted passenger? Otos are reclusive enough in my tank that I don't really know what's normal or not, 7 of them disappear in a 450lt tank. Hopefully you can point me in the right direction! I do have dewormers available (both Praziquantel and Levamisole) if necessary although I don't relish the idea of dosing a tank of that size. The tank has loaches and Corydoras in it as well so if there is tapeworm or otherwise present I would expect it would have spread to them too by now.
So far I have one rotund Oto and some of my loaches that I had thought were full of eggs too, but now I'm concerned for worms. On the other hand, I haven't seen any symptoms in any of the other fish (rainbows, gudgeons, tetras).
Thanks for all your help over the years, sometimes it's just not possible to Google an answer for something (not a lot of people have taken detailed pictures of their Oto's vents!).
<Agree with you that this structure seems abnormal. Might be a slightly prolapsed colon, which sometimes happens with fish, and fixes itself once the underlying problem is solved. Antibiotics are generally recommended here, but time and good water quality may do the trick, perhaps alongside
some use of Epsom Salt as per Dropsy. But I'd be veering more towards worms, given the tendency of wild-caught Loricariidae to be so infected.
Hope this helps, Neale.>

Unwell Otocinclus (Bob, is this another Pima/Melafix failure?)<Seems likely. B>     7/30/18
Hi guys
I have an issue with an Otocinclus.
<I'll say. It looks as if he's lost his skin and flesh right down to the bone.>
It’s seems to be a fungus but I am not sure.
<Not so sure. I'd be thinking a bacterial infection in the absence of fluffy threads, and medicating accordingly.>
I have 5ftx3ftx2ft tank with plenty of algae to keep 18 of these guys busy (they are all fat and were healthy) about 6 weeks ago I purchased 10 to add to the 9 I already had in the tank. After a few days I noticed that one had a medium white spot on the back of its head, (not sure if the sick fish was from the old batch or new) I treated the tank with Pimafix antifungal remedy
<Unreliable at best.>

with slightly less amount then the directions on the bottle.
<Why less?>
Unfortunately after 5 days of treating the tank the little guy didn’t not make it.
<Indeed. Pimafix (and Melafix) suffer, in my opinion, in being unreliable. By the time it's apparent they're not working, the fish is so sick treatment has become much harder, if not futile. I'd also make the observation that the idea a "natural" product is safer than one from a laboratory doesn't really have any scientific basis, and neither product would be by go-to product given the abundance of tried-and-trusted organic dyes, antibiotics, and indeed even copper-based products that are known to work and have low (or at least predictable) levels of toxicity.>
After day 7 I did a 50% water change and everything seemed fine with the remaining 18 Otocinclus until today when I found a large female with the same white patch, at the most the patch has been one day on her.
<See, I don't think this was a good batch of Otocinclus. I feel they're underweight, and while you're probably doing your best for them, they may have been in the retail tank so long that they're already half-starved. Rickettsia-like bacterial infections are a known problem in Loricariids, exacerbating any underlying health issues. Again, antibiotics may help, and certainly offer more hope than Pimafix or Melafix.>
Ph 6.8
Temp is 28
Tank mates are cardinal tetras, rummy nose tetras, red rainbows, Apistogrammas, flying fox and Bristlenose catfish. The tank is medium planted and the other Otocinclus are healthy and belly’s always full.
The large female is fine (eating, swimming, full belly) beside the patch on her head.
I tried to separate her into a quarantine tank to treat but she became very stressed.
I have attached photos below although the photos do not show the “furry” parts of the patch well.
<Indeed, not apparent to me at all.>
Thank you in advance for your help.
<By all means treat for fungus alongside bacteria, but the latter would be my prime focus. I'd also beef up their diet considerable, certainly beyond mere algae, to include things like Hikari Algae Wafers and even very small morsels of fish fillet or shrimp. They're going to need protein and fat to bulk up quickly, and algae alone won't do that on its own. Hope this helps, Neale.>

Re: Unwell Otocinclus      7/30/18
Hi Neale
Thank you for your quick response.
<You're welcome.>
The reason I under dosed mainly cause I thought the Otocinclus might be a little more sensitive, and it was only 10 ml.s under what was required.
<Unless instructed to do so by a vet, I would always use the full dose as described on the packaging. Simple as that.>
Can you recommend where I could get antibiotics to treat this problem?
<If you're in the US, antibiotics can be obtained from many pet stores or online. Products such as Kanaplex and Maracyn Plus are popular choices working well against many types of bacteria. Outside of the US it is normal for antibiotics to be prescription-only, so you either contact a vet, or else choose an antibacterial product sold in pet stores that won't be an actual antibiotic. I live in the UK, and recommend a product called eSHa 2000. It's inexpensive; doesn't seem to stress sensitive fish, even puffers; and best of all is reasonably reliable against both fungi and bacteria. So to some extent the recommendation will depend on where you live.>
Do you think I should continue with the anti fungal or start anti bacterial treatment?
<Yes, you can use anti-fungals (such as Methylene Blue) alongside antibiotics. Some antibacterial treatments will also treat fungi, so they're a good option too. I would avoid the 'generic' treatments such as salt or anything using tea-tree and similar oils, and focus on proper antibiotics (or at least reliable antibacterials) alongside trusted anti-fungals.>
Can I run treatment for all three or best to start with antibiotics then try to work on the others disease?
<See above.>
By underweight wouldn’t there full bellies mean they are eating well?
<Yes, but if they're eating low-protein food, such as algae, their bellies can be full, and they may have sufficient energy to swim about, but the fish don't actually grow much muscle and bone, or for that matter repair any underlying damage or infections. Let me stress that Otocinclus are aufwuchs, not just algae, feeders in the wild. They're consuming the "biofilm" on rocks containing green algae plus various tiny invertebrates (likely micro-crustaceans, rotifers, tiny worms, etc.) found therein. It's a difficult diet to replicate authentically in the aquarium, hence our reliance on a mixture of naturally growing algae plus some sort of protein-rich supplement, such as minced fish, frozen brine shrimp, etc.>
Most the time they belly’s look they are about to burst. I have started to add soft (boiled) zucchini to their diet as well.
<Again, while softened plant foods are an excellent supplement, plants are generally protein-poor, with notable exceptions such as cooked peas; fortunately, peas eaten by most fish if sufficiently hungry. At a pinch, you can also try cooked egg, especially hard boiled yolk, and old school food for baby fish. While very powdery, boiled egg yolk is extremely popular with pretty much all fish, and is protein-rich. So use a tiny bit at a time (feel free to save some in the fridge; it'll be good for a day or two) and watch your little fish go nut! Don't overdo it, not because it's toxic, but because unheated yolk can make the tank very cloudy if you use too much at once.>
Thank you again for you help
<Glad to help. Cheers, Neale.>
Re: Unwell Otocinclus      7/30/18

Hi Neale
I have added new photos it seems the issues has worsened in a short amount of time
<Does look fungal in these photos, yes. Would treat for bacteria and fungi together though, just to be sure. Cheers, Neale.>

Re: Unwell Otocinclus     7/30/18
Hi Neale
<Aussie by any chance?!>
thank you very much for you help
<Most welcome. Cheers, Neale.>

Re: Unwell Otocinclus      7/31/18
That obvious ha ha
<It's an accent that carries into emails, perhaps?>
Yep Sydney
<Cool. My sister lives in Perth.>
Where in the UK are you?
<Berkhamsted. So nowhere interesting!>
<And to you, Neale.>

Re: Unwell Otocinclus       8/3/18
Cheers Neale
<Glad to help.>

Re: Few questions
Hi Neale
Hope all is well
<Can't complain.>
Mate these Otos����‍♂️����‍♂️����‍♂️����‍♂️����‍♂️����‍♂️
So this thing that attacks the back of their heads seems to be coming back..... everyone of them started with this mark on the back of their heads (as seen in the photo) then it turns into the fungus and I lose the fish.
Do you recommend using the API anti fungus and bacteria?
<I'm not aware of this specific product.
If you mean the API Fungus Cure alongside the API Fin & Body Cure, then yes, that'd be worth doing.>
I have the Bristlenose with eggs which I can separate from this tank
<Wise, but the eggs would probably survive. Even if they didn't, another batch of eggs would likely appear very quickly.>
As always I appreciate your help and advice
<Glad to help, but not convinced we've made much progress yet! Cheers, Neale.>
Re: Few questions
Thanks Neale for your reply
Cheers mate
<No problem and good luck.>

Deworming zebra Otocinclus question      12/24/17
<Hello Andrew,>
I recently got 4 zebra Otos, from 2 different stores. They have been at the store at least a month (some of them have been there for two months).
They're not super skinny but not super fat either. Given this I suspect they don't have any overly severe issues, but my default assumption is that wild fish like these will have some sort of intestinal parasites.
<While that's possible, the biggest source of mortality with Otocinclus is plain old starvation. These are small fish, and like other small fish, probably have enough body fat (or however fish store energy) to easily last a couple weeks. Beyond that, they're in starvation mode. This matters because from the point of capture to the day they're introduced to the home aquarium can easily be months, and in that time they're usually not getting anything close to sufficient green algae and micro-invertebrates to keep them well fed. So while there's no harm -- and probably some benefit -- from the standard issue PraziPro de-worming treatment, I'd be more worried about getting them to eat properly. A bright light over the tank, ample green algae, plenty of oxygen, and lowish temperatures (22-24C/72-75F is optimal) are the order of the day here. If you don't have sufficient green algae -- and that's the algae they need -- then good quality algae wafers, such as those from Hikari, do the trick nicely.>
For now I have them in their own 5 gallon tank where I can easily observe and feed them.
I have seen it suggested that Praziquantel followed by Metronidazole is effective. Does this sound like a good protocol?
<Yes, though any particular reason you want to use Metronidazole?>
How long should the treatments last?
<Do follow the instructions on the packaging. Combining medications is possible if the manufacturers state it is, but honestly, unless dealing with a critically ill fish, I prefer to handle things in a more organic way -- start off with optimal diet and living conditions; if warranted, de-worming; and only if the fishes were still not responding positively, would I break out the antibiotics and/or Metronidazole.>
I have not had good luck in the past with getting fish to eat medicated food.
Thanks, and a happy holidays to the team,
<And to you, enjoy your winter solstice festivities! Cheers, Neale.>
Re: Deworming zebra Otocinclus question      12/25/17

Hi Neale,
Thanks for the response!
<Most welcome.>
There's no particular reason I want to use Metronidazole, other than that I've seen it suggested. My guess was it may help with some parasites that Praziquantel may miss.
<Possibly. Metro is primarily used (with fish, at least) for Hexamita and other protozoan parasites.>
But based on your comments I'm guessing it's rather harsh on the fish?
<Not aware of any specific problems in all honesty, and Metronidazole is often used with quite sick fish when nothing else will help. It's more a cost/benefit thing, in my mind. Look at it this way: Otocinclus are inexpensive, and if you buy ten, and one or two die, but the others sail through quarantine and fatten up nicely, that's going to be a lot cheaper than buying a smaller school of Otocinclus and medicating with PraziPro and Metronidazole with the aim of ensuring all of them survive. No guarantees, mind, either way! But with small, cheap fish, I'm more minded to buy slightly more than you want, fatten up with optimal diet/environment, and then see what happens before medicating.>
Thanks again,
<Welcome. Neale.>

Otocinclus death      10/22/15
Hello, i told you in my last message that i had got 5 Otocinclus along with a Farlowella and a Sturisoma...
<Mmm; okay>
Well today i did the usual water change (30% every 5 days) in my planted tank and i noticed one of the Otocinclus had trouble attaching to stuff and was sort of "drifting" while making weak jerky movements to stay on an Amazon swords leaf...
<Yikes; sounds/reads like there may be "something" troublesome with your new water... Nowayears quite common. I strongly suggest that whatever you do to prepare the change out water, that you store it a week in advance of its use.... this gives time for settling out of some materials, release of chloramines.... Alternatively, there are carbon/GAC et al. filters one can employ to eliminate the vast majority of untestable, deleterious and not aspects of new water.>
The rest of the suckermouths are doing fine, active and react to movements, contrary to the sick one. I do notice it has a bulging belly and it is sort of reddish near its anus.
<Yes; Otos are more sensitive than the other Loricariids mentioned; more so than most petfish>

I checked parameters and everything is fine ( no ammonia nor nitrites and 20 ppm nitrates)
<Ah yes; of the "things" we can easily test for... there are MANY other aspects, qualities of water>
The tank does not have a buffeting current but it does have two powerheads at the sides. During the day the surface disruption is minimized and the filter outtakes are aimed horizontally as i use them to diffuse CO2... during the night the outtakes are aimed at an angle to disrupt the surface and an air stone is tuned on...
As of right now the little guy/gal is not moving anymore and i assume is dead, he is not even reacting to my hand near him...Is there not enough oxygen in the tank or was this guy doomed from the start when i got it from the lfs?
<Again; my guess is on the "something" in the new water.... >
he/she seemed fine then... i did get them on the second day they were in store though...
<Oh! Well; I would encourage you, all to wait a week or more on such new arrivals... to allow the new Otos to rest up, reduce the chance of anomalous losses>
<Thank you for sharing. Bob Fenner>
Re: Otocinclus death        10/23/15

I always mix my water changes with distilled water to keep my ph and hardness down as my water comes at about 8 ph, I just wonder if the fish was acting like this for a while and i just didn't notice up until now... (keeping track of 5 different Otos in a 40 gallon jungle planted tank is sometimes... hard).
<Mmm; maybe>
The rainy season has just started about a week ago though so there may be something particularly nasty coming in the waters (Salvadorian rivers are very polluted).
<I see... potable water around the planet is disimproving>

When doing water changes i normally let the water sit for 2-3 days with aquaguard plus as conditioner, this supposedly removes chlorine, chloramines and heavy metals... But it could be that Otos are indeed more delicate.
<I'd wait a good week. There's a protocol on WWM...>
Also, the 40 gallon has ich,
<?! This could weaken the fish/es sufficient to cause their demise. Doesn't have to be "spotted" to be infested
im pretty it hasn't been the suckermouths that brought it as none of them has whitespots, and also because the store i got them from quarantines fish for a week and they are normally honest when fish have come out sick or have had something while being quarantined (i don't add the lfs water to my tank either, that water is full of chemicals).
So far the ich has presented itself on a black neon tetra, a cardinal tetra and the single female platy in the tank and they are about 2 o 3 spots, no dwarf cichlid, kuhli loach or catfish has whitespots... so... there are a few things i have to address about my tank.... fish will be treated with 30 C and salt in a quarantine tank with daily gravel vacs
<Good; treat all. PLUS I'd be elevating the temp. in the main/display tank>
Last time i had ich (also the first) it was a full scale attack and i thought i would lose everyone, but, i managed to cure it with just 32 C temp for two weeks, no salt and no medications, no plants died but one platy did... i wont be doing that because of the suckermouths though...
<? Why? They can take the higher water temp.>
however, i have quarantined the fish and did a quick but full gravel back (about 10% water change). I think the ich came from a lotus plant i added to the tank recently ( i do quarantine plants for 6 days though...and change their water every 2 days or so... seems like it was not enough).
Can there be a slight possibility that the ich has only affected the mentioned fish and removing them from the tank will potentially avoid a total outbreak in the tank?
<Unlikely no. Most assuredly ALL are infested>

last time when i thought i had cured the fish a single kuhli still had 2 or 3 whitespots but they disappeared and never saw ich again, that was 5 months ago...
<... a balance, "struck".... Again, PLEASE read on WWM Re freshwater Whitespot disease.>
Thanks, again
<Welcome. BobF>
Re: Otocinclus death        10/23/15

Oh, they can?
<Mmm; outside their natural range; but better to crank up aeration and raise temp. than lose them>
i thought they were slightly cooler, what about the black neons and (blue)neon tetras?
<See Fishbase; e.g.: http://www.fishbase.org/summary/otocinclus-vittatus.html>
I know that the cardinals, Apistogrammas and Kuhlis can resist (and in fact, like) the higher temps because when i treated with 32 C last time they were very active and colorful, if that's the case, then could i just do like last time? treat ALL the fish in the main tank with 32 C for 2 weeks with no salt and no medication?
<I would try this myself; rather than moving, treating elsewhere>
i really like that approach as i don't have to deal with added stress due to chemicals or salt (Kuhlis!).
the whitespots just appeared yesterday, but i know that they could have been infected days ago (Otos were added like a week ago and the lotus was added 3 days ago... so lets figure). Hopefully im in time to avoid catastrophe. Can i keep with my normal plant husbandry during the 2 weeks? (e.g. CO2 diffusing during the day)
<Likely so; yes; but with added aeration as mentioned>
I have read about ich, know its life stages and know it can be present in all its stages at once, but i thought the thorough rinsing of the plants
<I'd use a dip; alum or such, KMnO3... to eliminate snails, Protozoans....>
could have only left the tomonts. Still it just puzzles me how i kept the plants in quarantine for 6 days yet they are the primary suspects of contamination...
<Ichthyophthirius can be very persistent, "lay in wait", dormant if you will, in most systems>

but will re-read the article and faqs, looking for similar cases.
Thanks, again, re-reading right now the article
<Welcome. B>
Re: Ich!      10/26/15

Hello, again!
I am letting you know how everything is turning out...
<Ah, good>
The 40 gallon had an original stock of: 5 dwarf cichlids (Ramirezi, a pair of cacatuoides and a pair of macmasteri), 15 kuhli loaches (varied), 6 Cardinal tetras, 4 black neon tetras, 5 neon tetras, 1 female platy, 5 Otocinclus, 1 Farlowella vittata, 1 Sturisoma aureum. After the treatment for ich initiated i moved all the neon tetras to a quarantine tank and treated them there with salt and daily water changes of around 10% (substrate siphoning), no high temp, but water temp is around 27C. The 40 gal main tank is only being treated with high temp (32C), no medicine and no salt, i COULD try half dosing "super ick cure" (malachite green?)
as i have used it before at half dose without problems with the Kuhlis or the plants... what do you think?
<Best to avoid if you can here>
im hesitant this time because of the Otos, the Farlowella and the Sturisoma...
<Wise. Tienes razon>
I also checked the fish on fishbase.org and 32 C is above the natural range for all of them, however, they are very close to it (around 26 to 28 C). I decided to move the neon tetras elsewhere because their high end of their temperature range was 24C and the general consensus on the net is that they wouldn't resist anything higher than 29 C. Added an extra air pump too.
So far the cardinals have dropped their spots but a few more have appeared on fish that previously didn't have any: Otos and other black neons, there is a particular Otocinclus and black neon tetra which have a lot of spots, probably around 12 or so, they don't seem bad though as they are as active as ever... Dwarf cichlids, Kuhlis, Farlowella and Sturisoma have yet to present any spots. I know ich can get worse just before disappearing and that the fact that all the fish are eating is a good sign, i mean, i have treated fish for Finrot, fungus and revitalized near-starved fish back to full health but ich just makes me so unsure and worried... its actually getting on my nerves and im on this semester´s finals which doesn't make it any easier haha.
Can this treatment suffice?
<I'd continue it; but perhaps so>
it did work last time but im now treating more delicate fish, so im unsure if i should do anything else. Also, i was of the notion that ich couldn't lie dormant?
<Oh yes. Verdad>
if it can indeed lie dormant does it mean that it could effectively exist in every system?
<Tis so; te recuerdes>
Fish health seems to come into play on how easily(or badly) they get infected... could fish "always" be infected, but mildly ? (e.g. not noticeable)
<Si; possible>
and when water quality drops or a newcomer (generally less healthy than the fish already in the system), it could become easily infected and show the spots?
This disease is very weird, it is not at all acting like last time (when it did a full attack on every fish in the tank) it is now more... passive.
<And it turns out there are different "varieties" of Ich as well....>
Thanks again.
<Nos vemos, Bob Fenner>

Otocinclus Paralysis? – 12/03/12
To whom it may concern,
I have been traversing the great ocean that is the internet in search of information but cannot find any. You guys are my last hope.
I will provide you a summary of my issue first: I purchased a sick fish.
I'll admit it- I was dumb. I have been wanting an Otocinclus for quiet <quite> a while and was very disappointed when, upon arriving at my LFS, the only specimen they had was very ill. It was laying upside down in the tank seemingly unable to move, gasping.
<Not atypical for this genus... need high dissolved oxygen, rapid running water; some are sensitive to common water quality issues; often starved for food>
I came back a few days later and it was still there, still gasping, still on its back. My pity overwhelmed me and  I bought a guppy breeder/isolator
<Can't live in this>
 and took the little guy (or gal) home.
I have been keeping it in the breeder thing (stuck to the side of the tank w/suction cups) since I got the fish five days ago. When I first brought him home, he was so emaciated  and his tummy was so concave that he looked like a boomerang. I have been providing him with broken-up algae disks and algae covered leaves from the plants in my tank, weighted down with pebbles. His tummy is pretty much flat (instead of concave) now and I have found poop in the breeder tank, so I figure he's been eating.
The problem is that he still acts like he's paralyzed. He won't attach to the sides of the tank or to the leaves (that I've seen) and usually if you create a current with your hand, he just rolls across the bottom like a tumbleweed, making to attempt to move. He often lays still, gasping and twitching slightly.
He *can* swim, though. Sometimes, he will swim around extremely quickly in short bursts, as if he were panicking. After these bursts, he returns to his paralyzed state.
<Move it out of the container>
I want to be able to let him loose in my tank to give him free access to all the food (algae etc), but I'm afraid if he lays on the bottom and doesn't move even when touched, my fish will pick on/nibble on him.
<Not likely. I'd move>
Relevant tank info:
20 gallon planted freshwater w/small, smooth gravel substrate
Fully cycled (has been running after cycle with fish for 7 or more months)
Water parameters cannot be provided at the moment because I do not have an accurate testing kit. My kit seems to show very low or nonexistent levels of nitrite and nitrate, pH of around 7.0. If requested, I will provide more in-depth water values.
Temperature is usually kept between 77 and 83 degrees Fahrenheit Filters: under-gravel (came with tank) and power filters (power filter recently installed and is rated for tanks 20-30 gallons)
There is a lot of water flow and oxygenation as there is an airstone, two bubbling columns from the under-gravel, and a huge waterfall of water coming from the power filter.
I vacuum out the gravel around once a week which usually results in a 25% water change.
Other fish: 1 juvenile Black Ghost Knife (less than 5 inches),
<Needs more room than this 20 gal>
 1 male fancy guppy, 5 ghost shrimp, 1 golden mystery snail. I fully intend to upgrade tank size sooner rather than later in order to properly provide for my ghost knife.
I keep the tank lights (pretty bright w/UVA etc to simulate sunlight) on for anywhere from 11 to 12 hours per day.
Is this issue caused by the stress he endured at the LFS?
<Most likely yes; along w/ other trials along the "chain of custody", getting the fish to you>
He seems to be improving but needs to be much better to be loose with my fish. Thanks for any information you can provide for me. I really want the little guy to make it.
p.s. will I receive a reply via email? Thanks!
<Ah yes; welcome. Bob Fenner>
Re: Otocinclus Paralysis? – 12/03/12

Bob, (or other crew member),
Thanks for your quick reply! So from what you said, you assume it's just a stress reaction?
<Mmm, okay> I should refer you to my article here:
and the linked FAQs files above>
The LFS doesn't seem like they were treating him well- there was obviously no algae or food in the tank for him to nibble on.
My ghost knife is not yet aggressive and does not eat live food, so I guess I'll trust you and let the Oto out of the guppy breeder when I get home.
If it's just a stress reaction, then there's not much I can do other than try to let him live, right?
<If I understand what you mean here; yes>
 My tank definitely simulates (in my opinion) a running stream or river with the strong flow and oxygenation, which is what you said he needs, and it has a pretty well established algae growth on two sides and on the leaves of my plants (it's not hair algae)
<Ah, good>
As for the tank size, I am aware that it is not big enough for my ghostie.
I am currently in the process of purchasing a medium sized tank (50-55 gallons) for my fish, just haven't had the time yet. Thanks for your advice and knowledge. I'll probably bother you guys again if there's no improvement or if my fish bully him.
<Never a bother>
<Welcome. Bob Fenner>

Oto with a red belly    7/14/12
Many thanks for the excellent information I've already gleaned about Otos from your pages, but no answer to my particular question. One thing is they don't have algae to eat now, because they ate it all. No luck growing any so far. So, I feed Omega One Veggie pellets, Hikari algae tab and pieces of seaweed sheets, also by Omega One, as well as Microworms, banana worms and now and then Hikari frozen bloodworms. I also dose the tank with Nanochloropsis algae that I culture, as well as marine invert liquid foods.
Those last two are for some fan shrimp and 3 small FW clams. I recently got some Golden Pearls in the 5-50 micron size also for the fan shrimp and clams as well, first fed a bit of that today.
<Very nice>
Temps when I started the tank in the spring stayed around 70 F,  but with the summer heat, it's now around 82, unless I run the fan all the time.
That really increases evaporation but it would keep temps' around 70 F and I wonder now if I should simply run the fan and keep it cooler.
<Worth trying>
 Filtration is an AquaClear 50, plus a large sponge and a small internal corner canister both running on air. 3 big pieces of wood, some smaller ones with moss on, rocks, a good number of rooted plants with more on the way, plus a lot of ferns, on Eco complete substrate. Lots of Indian fern floating, as well giant duckweed. It was going to be a planted tank but I found I missed having fish. 30 G, been running since about March. Tankmates include Kuhli loaches, Whisker and Ghost shrimp, fan shrimp, some Danios, vari-coloured Mystery snails, and some Nerite snails. I feed the snails too, to help stop them eating plants.  Parameters have been reasonably stable. When I started, Ph was quite high, near 8, & our local water is very hard.  But tap is my only option, this is an apartment.
<Can, could mix in a bit of RO...>
 I use Prime to dechlorinate. I think because of all the wood, the Ph now stays a bit below 7. Nitrite 0, Nitrate around 20 ppm. Weekly or biweekly water changes, if it's very hot I do them biweekly.  All the shrimp are breeding, as are the snails. I recently lost 3 long fin Gold Danios, never even saw their bodies, nor any sign of illness. They just weren't there one morning. I assume they were eaten by the shrimp.  Normal finned Danios are fine though. One looks like it's full of eggs, hope I can spawn her. Then about a month ago, I got 8 Otos. Last time I got a look at all the Otos, I had six left. I think now I have 3 or 4, but they do hide very well most of the day, which makes it hard to know precisely how many there are. They come out after sunset, usually. Right now, no lighting on the tank, due to the heat problem.
But today, I saw on Oto on the glass, near the top of the tank and he worried me. They aren't usually out in the daytime, for starters. We did have a bad heat wave a couple of weeks ago and the tank got to 90 F,
<Yikes! Leave the lights off during the daytime when it's very hot>
 before I realized it and got the fan going. Then it got down to 70 in a few hours time, so that day was not a great one. Temperature hasn't been over 82 since that day and I don't run the fan constantly, so it has not dropped to 70 again either.  Whether that's relevant I am not sure. The Oto had a nicely round belly, but it was a disturbingly bright red colour, from the inside, not on the skin. Did not look swollen, just very red.  I wonder if this red colour could indicate an infection and if so, what I can do about it?
 I've learned these fish have a nasty start at being pets,  though I am doing my best to feed them appropriately, given the lack of algae in the tank.  I will be upgrading my lighting soon, which will hopefully help with algae growth. I now realize the shrimp and snails compete for the algae, which is no help to the Otos. But for now, all I get is a bit of the brown stuff in the uplift tubes, which the Nerite snails seem to love.
<Mostly diatoms I'd wager>
I can set up a QT if need be.. though I haven't one at the moment. I had to take it down because it became infested with scuds and I haven't got it back up yet. I'd really like to do right by the Otos, though I know now I did not do enough research on them before I bought them. Not my usual style, but mistakes happen, sadly. LFS also said the local hard water and higher Ph was not a problem and that Otos need warmer temperatures, which I now know is incorrect.  So I hope I'm not about to lose another Oto. Any advice deeply appreciated. Thanks so much, Karen
<They need high dissolved oxygen, some current... not too high temperature for most species. Bob Fenner>

to euthanize or not? :(   7/11/12
Dear WWM,
Well, you can tell from the subject line that I have a sad question. We had a nasty heat wave last week, and, in spite of my efforts, my tank got too hot. (BTW: 12G planted, established for some years; regular water changes, good water stats; 1 Nerite snail, 2 dwarf gouramis, fewer oto's than last week, possibly just 1 now.) We had one confirmed Oto death, and 2 are MIA and presumed dead.
<I really like the genus Otocinclus... but they do have issues w/ small volumes, low oxygen situations>

The last has been swimming around, eating and pooping almost like normal, but he looks terrible: his fins are a little... deflated? Without the usual lovely Oto fin perkiness. And the worst is this discoloration on his head - started as a small white spot between his eyes, but has expanded so that most of his head, down onto his snout and back behind his neck, is now white.
(I know oto's are a problematic fish, so I do want to say that I've kept them for a while and they have flourished; the surviving guy is probably 11/2 or 2 years old. That is, it's the heat that killed/is killing them, I'm certain. I also decided not to replace them; they're too delicate. I'd be happy to hear suggestions for alternative algae eaters in a small tank like mine, incidentally...)
<SAE's.... for a while; started small. Please read here re:
and here: http://www.wetwebmedia.com/FWSubWebIndex/algaeeaterfaqs.htm>
I don't know if there's any chance of him recovering,
<Some; yes>
 although I certainly hope there is. However, if he's suffering and there's no chance of recovery, I feel like I should end it. In your experience, can an Oto come back from this? If not, what would you do for / with him?
<I shy often on the side of hope... I'd hold off here; increase aeration if you can; be patient. Bob Fenner>
Re: to euthanize or not? :( 7/11/12

Thank you! The little guy is still bumping around, and his fins are looking perkier, but that white head is downright ghastly. Do you know what causes it? In reading around, I've come across a number of people who've had the same experience, but no identification of the problem, and no suggested treatment. Just a severe stress reaction?
<I do think so>
 Anyway, I've done my best to up the aeration, and at least the weather is cooperating a bit, so the temp is back in the safe range. Fingers crossed for now.
Thanks also for the SAE links - I am so fond of Otos and thought it might be nice to have a similar kind of fish, but it seems like my small tank could only handle
<I do so look forward to many other species being offered in the U.S.>
1. Maybe I'll just stick with the gouramis and snail for now - an understocked tank never hurt anyone, after all. And my last attempt at shrimp just resulted in fat gouramis...
And a general thanks: after not having been on it in a few months, I had a great time yesterday and today browsing around the WWM site, it's a wealth of accessible and clear information, and I always check it out before making any changes in my setup.
<Thank you for your kind acknowledgement. BobF>

Otocinclus catfish lying on side and back, won't eat, jerky swimming, fin twitching... Free ammonia, nitrite present    3/7/12
Dear folks at WWM,
I bought 2 Otos yesterday and introduced them into my 5-gallon Fluval Chi tank (system parameters below) to be tankmates with my male Betta fish.
Both Otos have normal-sized bellies and were both quite active until a few hours ago, when one of them very suddenly developed these symptoms:
  - unable to swim effectively; he takes a few strokes and then abruptly
  stops moving, sinking to the bottom
  - when he sinks he occasionally lands on his back or side
  - left fin twitches occasionally
  - ceased attaching his sucker to anything entirely (won't feed or rest on   decor)
<Mmm, I do hope that in the intervening period, this Oto has recovered...  the genus is actually quite touchy on being moved, placed in new
circumstances... not an easy-adapter to changing, unestablished settings>
I think it's possible the Betta might have attacked and injured him,
<Nah; unlikely>
though there are no visible signs of injury.
The Betta has chased the Otos a little bit, and occasionally flares at them, but this was mostly during the first day of their presence; he has since stopped chasing for the most part. I never saw him actually attack one.
<They're exceedingly faster>
However, now that the Oto is rather helplessly flailing about, the Betta seems to have taken a keen interest in him, occasionally stalking him until the he jerks away.
I'd like to get the Oto out of harm's way but I have no spare tank in which to quarantine him.
<Place a small colander, strawberry basket or such over this Oto, or place the Betta in a floating breeding trap/net or such (must be able to get to the surface)>
At this point I'm pretty certain the Oto is beyond recovery, but I want to know what caused this so that I can try to save the other Oto from the same fate.
System parameters:
  - established for a little over a month
  - 77-79 degrees F
  - 0.25 ppm ammonia
<... Toxic. Needs to be addressed immediately.
NEVER allowed as such to be added to the tank. This is likely the principal source of trouble here. See WWM re: http://www.wetwebmedia.com/FWSubWebIndex/fwcyctrbfix.htm
the linked files above, part. the Ammonia FAQs>
-- same as my local tap water. Unsure whether this is   NH3 or NH4+.
  - ~7.0 pH
  - ~60 total alkalinity
  - ~120 ppm hardness
  - ~1 ppm Nitrite (NO2)
<... deadly as well>

  - ~5 ppm Nitrate (NO3)
  - two live plants, two fake plants
  - about an inch of gravel substrate
  - filtered, but with minimal water movement
Any advice would be appreciated. Thanks!
<Read. Bob Fenner>
Re: Otocinclus catfish lying on side and back, won't eat, jerky

swimming, fin twitching Ok, thanks so much for your help!
<... did you read where you were referred?>
How do I deal with 0.25 ppm ammonia in my tap water? What should I do to remove the ammonia before adding the water to my tank?
<.... Don't write, read. B>

Also, I have another question: I use tap water to do partial water changes, but I also need to top off the tank once a day to compensate for evaporation. I was wondering about using Brita-filtered water for this.
I've heard conflicting information: it's good to keep the water hardness constant, but one should apparently "always use tap water". To me it seems that if I use tap water to top off the tank the hardness will rise indefinitely, since I'm replacing pure (evaporated) water with the same amount of hard water.
I'm not even sure if the Brita takes out those minerals in the first place.
Any idea?
Re: Otocinclus catfish lying on side and back, won't eat, jerky swimming, fin twitching

I did read where I was referred, and I couldn't find any advice on how to remove ammonia if it is already present in tap water to begin with.
<? The same means... chemical treatments, contactors/filtration media, or simply storing/aerating...>

 My apologies if this information is somewhere on your site, but I had no luck digging it up.
Do you have any advice on the other issue about the Brita-filtered water?
<A fine unit... useful for small volumes IMEstimation>

<Welcome. B>
Re: Otocinclus catfish lying on side and back, won't eat, jerky swimming, fin twitching
Sorry, what is IMEstimation?
<Think of IMO... In My... >
Re: Otocinclus catfish lying on side and back, won't eat, jerky swimming, fin twitching
–3/8/12br> Ah, I see.
<Clarity is pleasurable>
If the problem is the levels of ammonia (which I'm now addressing as best I can), then why is it that only 1 of the three fish in the tank is affected?
<Perhaps weakest of the trio...>
The fact that both the other Oto and the Betta aren't visibly affected, and this Oto is doing terribly and can barely swim, seems to point to a Betta attack, doesn't it?
<Not necessarily, no... By the same "logic", why wouldn't the Betta attack both similarly?>
I'm not familiar with how exactly the ammonia toxicity manifests itself in fish behavior, so I might be totally off the mark, but that's what it seems like given my limited experience.
<... stop writing; instead read, contemplate>

Re: Otocinclus with eyes missing 7/12/11
It's been several weeks and all four fish are doing fine, even the one with no eyes.
<Ah good>
They're with peaceable tankmates and are eating well. Thanks for your help!
<Thank you for your follow-up. BobF>

Question: Bloated Otocinclus with red streak on tummy - anything I can do to help him/her? (RMF?) <<Less food>> -- 05/07/11
Hi there,
<Hello Tracy,>
Your website is an invaluable source of information and I only wish I had found it sooner! I'm hoping you don't mind helping me a bit with my newest fishies... I adopted 5 Otocinclus five days ago, and brought them home to what I was told at them time was an ok, but I'm now thinking could be much better, tank. Here are its stats:
Marineland Eclipse 12 gallon Filter flow rate: 150 gph Temperature: 76 degrees Ammonia: 0 Nitrite: 0 Nitrate: 0 Lighting: 13 watts, daylight (I think, it's the standard bulb that came with the hood) Flora: Densely packed with large Java Ferns (one about 12 inches tall!)
Before I brought the Otos home, the tank had a thick covering of algae on the walls, a lot of which seemed to be a standard green, and since the Otos have come home, I see that they've scraped off little spots in it, so some of it must be the type they like? I worry that few patches near the bottom are verging on blue-green (Cyano-ish, though I really have trouble distinguishing, since there seem to be many varieties in this tank) and I can see some green hair-type algae projections as well, though I've read that Otos won't eat this. I put a blanched slice of zucchini in the tank yesterday on a veggie clip and have left it there, and I've been offering and algae wafer or two for them to eat as well. I feel/felt quite confident that their feeding needs were covered.
<Green algae tends to need bright light; in dimly lit tanks you more often get diatoms, and sometimes hair algae and/or blue-green algae. Your aquarium has about 1 watt per gallon of water, which isn't much. I'd be surprised if you have any substantial quantities of true green algae. While Otocinclus may eat some diatoms, they don't eat hair or blue-green algae, so feeding them with some supplement is essential. For 5 Otocinclus, I'd offer a single Hikari Algae Wafer or similar 5 nights per week. That should be ample for them. Of course, if there are other catfish or loaches in the tank, it's unlikely the Otocinclus will get enough to eat. It's best to keep them as the only bottom-feeders, except perhaps snails or shrimps.>
As for the tank conditions themselves, I'm only now becoming aware of how sensitive these fish are, and that the problems with them don't just stem from starvation and terrible water conditions during transport. I wish I had read this sooner, but now that I have them, I'd like to do everything I can to keep them happy and healthy. The tank is currently NOT cycled, going the au naturel route with the massive amount of ferns taking up the waste products of the fish. (theoretically, and I'm testing each day to make sure that this happens. I'm also prepared with ammonia-free water to do a water change if need be).
<I wouldn't rely on Java ferns of this at all. Get some Floating Indian Fern instead. Java fern grows slowly, and plants that grow slowly absorb minimal quantities of ammonia. Now, your Java ferns certainly carried in some "good" bacteria with them, and as such, speeded up the cycling process. But the plants themselves won't have any beneficial impact on either water quality or algae control. Floating Indian Fern is an
undemanding species that grows at the top of the tank, and because of that, can grow quickly even under mediocre lighting.>
I had planned to cycle this tank at a later point, using Safe Start by Tetra (formerly Bio-Spira, the one/most effective bacteria--in-a-bottle product, from what I've heard) as my results have been mixed with fishless cycles in the past, and I don't have a source of clean, seeded/mature filter media at the moment. It was my plan that the plants would take up any excess ammonia during the cycling process and that the Safe Start would get things underway very quickly (and I would, of course, monitor very closely for ammonia while this went on).
<Good. Most of these "instant" cycling produces are hit-and-miss at best.>
Now finally to my question: one Otocinclus seemed more plump than the others from the beginning, but now he or she has become disturbingly so, to the point that I would call her bloated, and not just well fed. I've also noticed a red streak on his/her stomach, and I'll attach a few pictures to illustrate the bloating/streak. This fish's behavior doesn't seem that unusual, in my very limited experience with these fish. I've seen him/her grazing for food and moving around, and he/she has spent a great deal of time sitting stuck to the tank wall today. Given this, my questions are as follow:
- Should I isolate this fish from the others to prevent the spread of whatever is causing the bloat? - What should I treat him/her with? (I have Kanamycin and Epsom salt on hand) - Should I consider treating the other fish, as they've been exposed to this bloated tankmate, or just monitor them? - Are my tank conditions, as they are, likely to have caused this, and would you suggest an immediate change in them?
In advance, thank you so much for any advice you can offer. Your expertise is so appreciated!
<I would not treat this fish at all. Instead, I'd concentrate on ensuring good water quality through 20% water changes at least every 2 days, and ideally daily. I'd minimise feeding: half an algae wafer every 3 days, tops. After 6 weeks you can assume the tank is cycled and ramp the feeding up to the amount I mentioned earlier. Otocinclus have a dismal survival record in captivity because their needs are very specific. The aquarium should be mature with excellent water quality; water temperature should be
low to middling, 22-25 C/72-77 F; water circulation should be brisk, more than 6 times the volume of the tank per hour; and hard, basic water should be avoided if at all possible. Even under good circumstances losses are common immediately after import, but given the right conditions schools of 6 or more specimens can do quite well. Cheers, Neale.>

Otocinclus not eating (RMF, anything to add?)<<Nada mas>> 3/4/11
I have a 20 gallon tank with 6 neon tetras and 4 zebra Danios. I added 2 Otocinclus about 2 months ago for algae control. They appeared to be different varieties though because one was much larger than the other and their coloring patterns were different. They did very well for about 2 months and then while I was on vacation for a week the smaller one died. When I found the dead one I checked my water quality and everything was normal and none of my other fish were having any problems so I don't have any idea why it died. About 2 weeks after the small one died the larger one stopped eating and is not swimming much. It usually eats almost continuously so I know something is wrong. It looks healthy other than the change in behavior and a slightly larger belly than usual (coloring is dark, no spots or red streaks, no scales sticking out). It has been about a week since it stopped eating now. All of my other fish are still doing well with no signs of illness. I am very worried that it will die too. What do you think could be wrong with it? Could it have an intestinal blockage causing the larger belly and lack of eating and if so what can I do about that? Could it have some other illness that doesn't affect the other fish? Could it be 'sad' because the other Oto died? I would like to get another Oto to replace the one that died, but I'm concerned that if this one is sick it may infect the new one too. The algae is really starting to build up in my tank now that I only have one Oto left and it's not eating. What should I do? Please help!
<Hello Jessica. Among commonly sold fish, Otocinclus are among the most difficult to keep alive for any length of time. Sadly, much of the hobby treats Otocinclus as "disposable" algae eaters that simply need replacing every few months. In reality, Otocinclus require very specific conditions to do well -- lowish temperatures (22-25 C/72-77 F); high levels of oxygen; soft water (2-10 degrees dH); lots of green algae (not diatoms, hair algae, etc.); and the company of their own kind (six or more specimens). Every step away from this pretty stringent list reduces your chances of keeping them alive for long. Like many Loricariidae, Otocinclus likely come into the aquarium trade from the wild gut-loaded with protozoan parasites and commensals. My guess is that so long as your Otocinclus are happy, their own immune systems keep these in check, but once your Otocinclus are stressed, these parasites and commensals multiply and cause problems. This is certainly the case with Loricariidae such as those of the genus Panaque, notorious for being "delicate" upon import, with Rickettsia-like pathogens having been identified as part of that problem. There's really nothing I'd so in terms of medication, but reviewing environmental conditions, checking diet and social provision, and acting accordingly. For whatever reason, the similar genus Parotocinclus seems to include species that are significantly hardier, and Ancistrus and Peckoltia are even more durable, and BY FAR the better choices for casual hobbyists stocking ordinary community tanks. Cheers, Neale.>

Algae Eater with weird growth near gills, Oto hlth. 11/15/10
Recently I've purchased 2 Otocinclus and one of them has a white bump/cyst between its gills.
<I see this>
I've had Otocinclus before as well as true Siamese Algae Eaters and Chinese Algae eaters, and I've read that Chinese Algae eaters start to have weird bumps/ growths as they age... But I was positive that I had bought Otos, though I'm starting to second guess myself... It has a dark strip going all the way down its side and is a speckled dark tan color.
From a belly view, its fins resemble butterfly wings. All physical indications say that it is an Oto, but I would like to know if I'm wrong.
Currently, I have quite a few fish in a 10 gallon
<Hard to keep such small volumes stable... and Otocinclus need stability in their water quality>
well established tank that I'm using to quarantine fish to go into my big tank. Ammonia: 0, Nitrite:0, Ph: 7, 84 degree Fahrenheit. The cycled quarantine tank is housing 2 small clown loaches,
<Will need MUCH more room; if/should they live>
3 platies, 4 zebra Danios, and the 2 aforementioned "Otos".
The reason for the high temperature is mainly to safe guard from Ick, since I know clown loaches fall quickly victim to that...
Anyway, I've only had the 2 Otos for about 2-3 days and I believe the
already had the bump between its gill when I bought him... He is active and happily cleaning the tank for algae, and it doesn't seem to be bothering him. Pooping fine as well. I have been searching around online and people have previously mentioned bumps to be tumors or lymphocytes... I just wanted to know if I should be worried, and whether this was something unusual or contagious. I have some pictures, but it was very hard to focus when the camera is so close to the tank glass and the "Oto" is so hyper. But hopefully, they will be helpful in at least discerning if this is indeed an Oto. :)
Thanks so much!
<This may be a sort of "goiter"... I would add food or liquid prep. of iodide-ate (like Lugol's) as if this were a marine system. You can search WWM, the Net, in-print references re this endocrinological/nutrient deficiency syndrome. Bob Fenner>

Bloated Otocinclus 9/3/10
Dear WWM,
<Hello Rebecca,>
I wonder if I can ask for your help.
<First things first. Please don't send 16 MB of images again! Just your message alone took up two-thirds of our e-mail space on this server. If anyone else sent a big attachment today, that would block the whole system, and every one else would have their messages bounced back. We do, explicitly, ask for photos to be cropped or resized down to about 500 KB each. That levels the playing field for everyone. It also means images download to my computer quickly, so I can get on and answer more questions.>
I have two Otocinclus in a small planted tank (28l) with a couple of shrimp and 5 platy fry which has been up and running for 8 months.
I have had the Otocinclus for 3 months and they have been doing really well.
<Good. A fussy species with a poor track record in captivity, but if they're still lively after 3 months, you're through the worst of it.>
They finished off all the algae in the tank within a week so I have been supplementing their diet with seaweed (rinsed, then soaked in old tank water for half a day to ensure there is no salt added to the tank with the seaweed). I've also tried zucchini, spinach and cucumber but they were never very interested in these.
<Indeed. Do try Hikari Algae Wafers as a useful alternative.>
I went on holiday and left my fish under the care of a very responsible friend,
<Almost always best to leave fish unfed if the trip is 2 weeks or less.>
but unfortunately a close relative of hers became very unwell and subsequently died so naturally she went to be with him, leaving my fish with some seaweed and a holiday block for the platys.
<These feeding blocks are lethal. Do NOT use them.>
This meant that my fish were left without a water change for 3 weeks!
<Which is why NOT feeding fish is better. Fish can go weeks without food.
If they're not eating and you nudge the water temperature down a bit, their metabolism slows down and the more importantly, the rate at which water quality deteriorates slows down as well. All these animals of yours will be happy at 22 C/72 C, so keeping them cool shouldn't be an issue.>
I got back on the same day as she did to find the tank a mess. I did a 50% water change with a siphon to clean the gravel and all the fish looked well at the time. Now 5 days later one of my Otocinclus is very bloated.
<I see! Was it bloated before you did the water change? It may simply have overeaten as a reaction to the change in water quality or simply you offering more food that it likes.>
I searched on the internet and found that they are prone to parasite infections and worms when the water quality is poor.
<Can be the case, yes.>
I tested my water again today and found the ammonia level was 0.25 ppm and nitrate 40ppm (nitrite 0ppm).
<Otocinclus are sensitive to ammonia, and to a less extent high nitrate levels.>
I did another 50% water change and rushed to the shop that sold me the fish. They thought that it sounded most like it could be an internal parasite, but also wondered if it could be dropsy.
<"Internal parasite" and "could be Dropsy" are code words for "Haven't a clue, but I'm going to sell your 15 quids' worth of stuff that won't work but helps my bottom line.">
I bought treatments for both, along with an air pump to improve aeration in the tank.
<Aeration is widely misunderstood. It doesn't add air or oxygen. Why should it? Without adding pressure as well, there's no reason air bubbles with force oxygen into the water. If it did, I could bubble CO2 through a straw and carbonate the cup of tea sitting next to me. Doesn't work like that.
What aeration does is increase circulation. As the bubbles rise they carry water, and in particular they're taking water from the bottom of the tank to the top. In doing this a cycle is created with bottom water going up and surface water being pulled down to replace it. This circulation ensures better distribution of oxygen since the oxygen is diffusing into the water *at the surface* where the water and air touch each other. There's no magic about bubbles. A good filter will circulate the water much better than air bubbles.>
The treatment for parasites is called Sterazin and contains Malachite Green, Piperazine Citrate, Formaldehyde and Acriflavine Hydrochloride.
<Malachite green and Formaldehyde are for treating external parasites; Piperazine works against worms. No reason at all to imagine this medication will treat anything else. Certainly not bacterial infections like Dropsy.>
The shop recommended starting with this as it would be less harmful to the fish, and recommended treating at half the standard dose. The other treatment is an Interpet Anti-Internal Bacteria treatment containing
Bronopol, Formaldehyde and Benzalkonium chloride.
<Have yet to see this product cure anything. Bronopol is an antimicrobial, but honestly, I've never been impressed by it. One problem with antibacterial medications is you need to add to the food or inject into the fish to get a useful dose. Vets will tell you precisely how much to add if you need to add to the water, because factors such as the size of the fish are critical. Anything based on drops per gallon is a long-shot at best.>
I'm giving you the ingredients as I'm based in England and I don't know if the treatments will be the same as the ones you are used to.
<Have used both these medications in years past. Neither are ones I recommend.>
I have treated for the parasites using half the standard dose as recommended, but now I am really unsure if I should be treating for bacterial infection instead and I would really appreciate some advice. I do not own a quarantine tank so I am having to treat the whole tank and just hope my shrimp and other fish come through this ok.
<Sterazin will likely kill the Shrimp outright. It does state this on the packaging: do not use with crustaceans! Specifically, formalin is highly toxic to them.>
I have attached a couple of pictures, neither of which is very helpful, but I think the side-on view does show how bloated his/her belly is.
<I wouldn't treat this fish at all. I'd optimise water quality, lower the temperature if needs be (Otocinclus will be stressed above 25 C/77 F, as will Platies), and ensure a sensible diet. Don't overfeed. Watch and wait.
If the fish becomes thinner again after a few days, you should be fine. If not, with fish this small, Dropsy-type conditions tend to be fatal anyway, so treatment is pointless.>
Many thanks in anticipation, Rebecca
<Hope this helps. Good luck, Neale.>

Oto Pics please? 2/9/10
Hello, Sorry to bother you guys again... but could you send me a picture of a healthy and an unhealthy Oto? bottom and side view is best. All the images on the web seem the same and I'm not good enough to tell them apart.
<Do see here:
As with other Loricariidae, healthy Otocinclus have convex bellies; unhealthy ones concave bellies. Very ill fish have sunken eyes. It's a simple as that. I don't really recommend Otocinclus for casual aquarists because they are delicate, need specific foods, and tend to be short-lived in "average" aquaria lacking the oxygenation and water flow they appreciate. Cheers, Neale.>

Sick Otocinclus - possibly columnaris, hope you won't mind helping 8/18/08 Hi WWM crew, <Ave,> First off, I'd just like to give my thanks for the tremendous help that your excellent website has already been with many issues that we've encountered as newer aquarists. We have a problem with one of our Otocinclus that I can't find a definitive answer to and would like your opinion on the matter before I start medicating, if you'd be so kind. Apologies that this will probably be very long, as I want to include anything that may be of relevance. <Oh...?> We recently (2 weeks ago) somewhat tentatively bought 6 Otocinclus (probably Macrospilus, but regardless the common variety with a grey body, black stripe and white underside). We slowly acclimatised these to our 10 gallon cherry shrimp tank, using this as a quarantine tank (factors being - it is 6 months old and thus we believe quite stable, is quite rich in algae and has c.20ppm Nitrate which is quite low in our Southern England liquid rock/fertiliser water). We have recently purchased a 4-stage RO unit which we are buffering with Aquadur plus, including the odd drop of iodine for the shrimp and also a small amount of Waterlife Vitazin multivitamins and Stress Coat. Current tank stats are TDS 413, pH 7.9, KH 8, dH 10 (not sure if I have my notation correct there - I mean general hardness), Ammonia 0ppm, Nitrite 0ppm, Nitrate c15-20ppm, temperature 22-23 degrees Celsius. <All sounds fine, though as you appreciate a little harder than Otocinclus might prefer. That said, assuming water temperature isn't too high (and you're fine there) and there's plenty of algae for them to eat, should be fine.> When we water change it's a 40-50% change once or twice a week (except see below for the past couple of days) with RO water buffered to as close to the TDS and KH stats of the water as possible - which amounts to TDS c 360, KH 8. <OK.> The only changes in water stats in the past couple of weeks are that the Nitrate got up to about 30ppm (I find the colours on the tests quite hard to judge) just before the last water change, I have also pulled the heater down to 22 from 24 degrees since discovering the sick Oto since I found out that Otos prefer it cooler and columnaris doesn't. <Otocinclus certainly do like moderate temperatures, as is the case with many of the llanos fish of South America.> I have observed no inter- or intra-species bullying in the tank. The only other occupants are about a dozen Red Cherry Shrimp, and the tank is decorated with bogwood, Marimo algae balls, java moss and a few floating plants, and a single artificial hollow log to add an extra hiding place. It has two small sponge filters and a small air-powered box filter (we were hoping the RCS would breed and didn't want to use a power filter for this reason, sadly they have not yet done so for some reason), and an additional airstone for more circulation and oxygen exchange. <I'd actually put the problem here (likely Finrot and/or Fungus) down to what happened between capture and introduction to your tank. They're delicate fish and almost always half-starved by the time you buy them. Attrition rate is very high, with many specimens dying no matter what the hobbyist does. Just treat the tank with eSHa 2000 (which does both Fungus and Finrot) and hope for the best.> As there is not going to be enough algae in a 10 gallon tank to support 6 Otos, and knowing that getting them to eat heartily is a key factor in keeping new Otos alive, we have been supplementing with a slice of zucchini or cucumber and Hikari Algae wafers. We also occasionally add another small wafer that the shrimp really love or a small pinch of ground up flake food. Fortunately the Otos took to both the offered vegetables and algae wafers, developed round bellies and became pleasingly indolent and seemingly happy, with no losses. <Ah, the shrimps won't like the eSHa 2000. In this instance, I'd suggest moving the catfish to the 10 gallon and putting half a Hikari Algae Wafer every other day for him to graze on. For the 4-5 days of treatment, that should be fine.> 60 hours or so ago I found on my morning check that one of the Otos was sitting on his own and had a white patch on his right flank just in front of and below the dorsal fin. This patch appeared white and perhaps fluffy (hard to tell from the angles I've been observing from) and much larger than I associate with ich, perhaps 4-6 mm in diameter. I couldn't tell if it was a fungal or bacterial infection, or perhaps just an injury. I was immediately concerned, especially when I found the 30ppm Nitrate, and performed an immediate water change to bring the Nitrate down to its usual 15-20ppm, and added standard doses of Melafix, Pimafix (I understand you generally don't rate these) and Stress Coat to help with healing. <Melafix and Pimafix are pretty unreliable, to be honest.> Over the past two days I have been observing, performing a daily water change and continuing the dose of Melafix and Pimafix. He has seemed happy enough when I see him - although perhaps slightly more reclusive than the others - but I have seen him eating several times. I have been concerned re: Columnaris, but decided to do nothing rash and observe. Unfortunately this morning I noticed that a patch of white (possibly cottony, but again very hard to tell) had developed around his mouth and now I want to take action. I don't want to needlessly transfer him to another tank (stress and shock from the inevitable difference in water quality, the netting and the separation from his Oto crew) and am unsure whether to medicate in the current tank, move him to another tank (we have plenty of spare tanks that we could use as a hospital) or do nothing if it's not actually a bacterial or fungal infection. <eSHa 2000 does Columnaris, so if that's the thing (though I don't think it is) treatment isn't complicated. One reason I like eSHa 2000 is that it treats Finrot, Fungus and Columnaris, sparing the hobbyist from telling them apart! It's also good with catfish -- in my experience.> We have tried to take photos which I attach the best of, unfortunately we don't have a camera with a great macro mode. <Good enough for government work...> We can obtain any medication readily available in the UK, having ESHa 2000, Myxazin, Permanganate and many others already, and I managed to obtain some Metronidazole anti-parasitic and Tetracycline by importing from the USA - although I expect neither of these are of help in this case, as Tetracycline is I believe a gram-positive antibiotic and Columnaris, if that is what it is in this case is gram-negative. <eSHa 2000 will do, assuming the specimen isn't so weak recovery is impossible.> I'm really not sure what to think - aside from the spreading white patches, the Oto is not acting ill, and I'm surprised if it is Columnaris that he's still alive, as I hear this kills in just a couple of days. We did have guppies previously with similar symptoms though, mostly affecting their fins, and it took several days for those poor souls to die. I am torn between doing something that may stress a sick fish and knowing it could drop dead at any minute. Apologies for the length - any advice you can give would be most welcome. Cheers, Paul C <Good luck, Neale.>

Re: Sick Otocinclus - possibly columnaris, hope you won't mind helping Many thanks, Neale. I have moved the sick Oto to bare cycled tank and treated as you suggest (and I'm very glad that we always keep a spare cycled filter, heater and airstone, would recommend some spare kit to anyone). Sadly the Oto is extremely weak and I'm not expecting him to survive. Fortunately the other 5 Otos look fine, and I'm aware that if I only lose one I'm getting off pretty lightly. <Agreed; you're well above the batting average for the species...> I just wish it were easier to find Otos that were bred in captivity rather than wild-caught, I've seen some videos of that and it's a wonder any survive all the way to our tanks. <Quite so. Interestingly though, once they get through the acclimation process, Otocinclus can be quite good fish if maintained in the right conditions. They're by no means "community fish", but far from impossible to keep.> I will consider pulling the hardness and pH of the tank down a little if they are to remain there long-term - but I'm proceeding cautiously, as we've come quite close to KH/pH crashes in our other mature tanks and have had to go with crushed coral in the canister. <I would suggest forgetting about altering water chemistry. I find mixing 50/50 rainwater with "rock hard" Hertfordshire water gives me adequate conditions for most species. There's no advantage to creating soft water conditions if that means pH varies between water changes. Far better to simply dilute the "edge" of the hardness, brining the pH down to 7.5 or so, and leave it at that. Most freshwater fish will adapt to this very successfully.> Thanks again, I very much appreciate the huge amount of time you put into giving assistance. All the best, Paul C <Happy to help, Neale.>

Illnesses with Oto Dear Robert, I actually have two questions. We recently bought 2 Otocinclus flexilis and they initially did well. However after about 1 week, one died and the other has stopped eating. Our water tends to run on the alkaline side but never higher than 7.6-7.8, <Otocinclus spp. don't care for hard, alkaline water... this or the stress/damage from collection, shipping could easily account for what you have observed> I tested the nitrites (zero), I generally do 25% water changes every week, no further apart than 2 weeks. We have 8 other fish in the tank (20 gallons) 3 upside-down catfish, 2 swordtails and 3 bleeding heart tetras. Of note, one of our swordtails was incredibly sick approx 1 year ago. We managed to nurse him back to health with 14 days of gram positive and gram negative antibiotic coverage as well as with CopperSafe (all in a quarantine tank). Since then, he has been fine. About 2 months ago, one of our tetras began swimming erratically (nose pointed upward, tail pointed down and appears to be frantically swimming but no getting anywhere.) He was moved to the quarantine tank as well. He's gotten a bit better (now he eats) but he still swims funny and now his tail is all frayed. I treated him for 14 days as well with Maracyn 1 and 2 and CopperSafe. (I've continued the CopperSafe). So, the two questions are: what's wrong with our bleeding heart tetra and did the Oto's get what he had (he had been out of main tank for nearly 1 month before we added the 2 Oto's) <This all sounds a bit eerie...> Also, I just read your article on the web and noticed that CopperSafe can do more harm than good to these guys. The Oto died today. I had added CopperSafe and Maracyn 1 and 2 to the tank this AM after noticing that both were acting sick (he was worse than his buddy). Did I kill him with the CopperSafe? <Likely this contributed to the loss> Thanks for whatever help you can offer. Brigitte Baumann <I would have your source water checked (by the supplying agency, a quality assurance lab...) and likely get/use a filtration system for your pet-fish as well as drinking and cooking uses... Please do look into a reverse osmosis unit... inexpensive, easily maintained. Bob Fenner>

Breathless Oto (01/31/2004) Hi Sabrina or however gets to handle we freshies tonight. <Sabrina here!> Don here, from the "Needs Clarity" thread of inquest. <Good to hear from you again, Don.> Tank doing great, still clear as a bell. Plants growing well. <Ah, delightful!> Have not added any fish since the cycle completed and the water cleared. Still 8 Zebra Danios and one Oto in a 55 gallon with an Emperor 400 and one small power head. 0 ammonia and nitrite. 15ppm nitrate. Not bad since my treated tap reads .5, .5, 20. <Sheez, not bad at *all*!! Plants are good things now, eh?> I have been doing 15 gallon water changes once a week. Got a couple of quick questions, but the Big Story on Action New tonight is my sick or injured Oto. <Yikes.> I noticed a him breathing a little heavier than usual yesterday. When I got home from work tonight he was breathing much harder. I noticed a pink area just behind his eye at the top of the gill slit. He let me get a pretty close look and it seems that the pink is actual gill tissue. As if a piece of the gill cover was removed, exposing the gill. I could see it pulse in rhythm to his breathing. Only saw one side up close before he darted into his cave, but the other side was also pink. <Although this may be an injury, it might also be that the gills are irritated, and so more visible than usual. Could be indicative of parasites in his gills; perhaps ich.> He's still in the 55. I have a 10 gallon I can QT him in, but the heater is inopt. I can pick one up tomorrow. <I would do so, if at all possible.> Just not sure what, if any, meds he should get. Still very active and feeding. He pounces on his daily quarter algae wafer. Always working the glass and gravel. No spotting or other discoloration. No scratching. All fins seem perfect and extended, no clamping. He would be great if he could breath! <For now, perhaps all that is necessary is observation - but if this is parasitic, it could transfer to your other fish; best to quarantine him.> Now a couple of quick ones. What type of paint is aquarium safe and will adhere to PVC? I made some caves by coating PVC tubing with aquarium sealer and rolling them in dry gravel. They look good, but a little of the white still shows. Thought I'd paint the tube brown first to eliminate the white. <You could use a two-part epoxy paint, like such that is used for swimming pools and sealing plywood aquariums.> And finally, what kind of glue can I use to make slate caves? I made a few using the sealer, but it takes too long to cure. Had a couple collapse while drying overnight. <You might try a gel-type Cyanoacrylate superglue.> Don <Wishing you well, -Sabrina>

Dying Otocinclus - Capture and Holding may be the Culprit Hello. I have two planted 30 gallon tanks. A couple weeks ago I bought 6 Otos to put in them to help with algae, and five of them died a few days ago. I'm running CO2 at about 20 ppm, overdriving 2 18 watt bulbs, pH is 7.0, KH's are 5-7. None of the other fish died. Haven't tested nitrates lately, but in two weeks prior to buying the Otos, I did four 50% water changes (I know that's a lot, but I haven't lost any fish in doing so). Prior to that, nitrates were about 10-20 ppm, so I can't imagine they were a factor. I can think of only two possible causes: 1) I have slow release tablets for my swords; perhaps the Otos were nibbling on one of those that got shifted to the surface somehow; or 2) I added Fluorite iron mix the day before they died. They recommend 1 mm/ten gallons, I perhaps doubled that, if that much. Never had any trouble before. Do Otos have a greater sensitivity to iron that most other fish? I'd rule out stress as a factor, since I have lots of nooks and crannies, and they were eating like pigs the day before they checked out. The one remaining munches continuously. I have tiger barbs in one tank, but they, nor any other fish, acted aggressively towards the Otos. I'm puzzled, because I'm told they're so hardly, except for high nitrates. Thanks very much, Mark < You Oto's actually died from starvation and or a vitamin deficiency. Oto's are caught in the wild and held for a long time. Maybe weeks before they reach the store. They need to eat a little bit every day to stay healthy. After such a long time their long intestine becomes depleted and they start wasting away. You buy them and they start to eat like crazy. Unfortunately algae has a very low nutritional value and they need to eats lots of it for a long time to build up their strength. Most of the time it is too little too late and they die. This happens with Pleco's too. The remaining fish then do Ok for a long time because there is lots to eat for them. Next time I would recommend that you only buy Oto's or Pleco's with full bellies. Not concave or hollowed out. Next , place them in a quarantine/hospital tank and feed live black worms algae wafers and guinea pig pellets. The worms will give them some instant digestible protein. The algae wafers will give them some binder with minerals. The GP pellets are vitamin C enriched alfalfa that supply roughage as well as protein and vitamins. Many of these fish require highly oxygenated water with a current. Many aquarists go without a strong current because they will lose their CO2.This will be very helpful for these little guys.-Chuck>

Question Re: Oto placement 12/10/06 Hi Tom, <<Hey, Sean.>> I have another question for you already. <<Let's hear it...>> I was at a major chain pet store today, and much to my surprise, they were selling Otos (Otocinclus) for $1.99. Since this is the first time I've seen them in my area, and that price is too good to pass up, I bought 3 (I read on WWM that they do well in groups). I have 2 tanks, and I can't decide which one they would do best in. <<The quarantine tank, Sean. (Being a little silly but I'll explain.) The store I buy my fish from, my Otos included, is, literally, a 'Mom and Pop' operation and won't sell their freshwater animals for the first two weeks after they take delivery, i.e. they quarantine them all. Saltwater fish are held for four weeks with cards posted on the tanks showing the dates that the fish arrived at the store. That said, I can guarantee that this isn't the case with your Otos. Point number one. Next, Otos are notorious for being difficult to acclimate. Wonderful little guys that they are, they're easily lost early on no doubt due to the stress of transporting, handling, lack of sufficient food and -- the big one -- means of capture. Because of their tiny size and naturally tangled environment, many (most?) of the Otos that reach the store have been taken in the wild using cyanide, or other chemicals, to disable them for collection. (I would be skeptical that 'tank-raised' Otos would be going for $1.99 each. Mine were $3.99 each which I thought was a bargain.) The upshot here is that these chemicals can remain in the internal organs of the fish either shortening their natural lifespans of about five years or leading to a much, much earlier demise. Darned hard on the Oto, to be sure, but if one is lost and picked at by another fish, it, too, may end up with contamination from the chemicals I referred to. Now, let's move on to your options.>> Tank one is a 24g tall/show tank, moderately planted, with a cheap "fizz tab" CO2 system. Its inhabitants are 4 Opaline Gouramis, Trichogaster trichopterus (2 are the gold variety), 2 paradise fish, Macropodus opercularis, 2 Ramshorn snails, and one common Pleco, who will be re-homed soon as this tank will be way too small for him (he's only about 4" right now). <<Sounds like a good choice, Sean. And, I appreciate your thinking regarding the upgrade for the Pleco.>> Tank 2 is a 5g, moderately planted, with no CO2. Its inhabitants are 1 Betta and 3 cherry shrimp. <<Could be a good option as well but, personally, I like to add some aquarium salt in with my Betta. Your Otos would 'tolerate' the amount of salt I use but I don't think they'd appreciate it very much.>> Both tanks have laterite and gravel substrate, a good amount of driftwood, and a pH just above 7. Neither tank has much of an algae problem, although both tanks have small amounts of green "spot" algae. Now, here's my question: which of these tanks would be a better fit for my Otos? <<As you may have gathered, Sean, I like the larger tank for your new pets. The smaller tank would likely work just fine but I'm not a huge fan of keeping Bettas with other fish. Just me, perhaps. Also, if you do decide to add salt to your Betta's tank down the road, and I do recommend this, it probably wouldn't sit well with the Otos if they were in the tank.>> Sean <<Enjoy your new fish, Sean. Tom>>

Bloated Oto 3/23/07 Hi Guys: <Patrick> I have an Otocinclus that is bloated. He has a bulging belly as you can see in the pictures that are attached. Problem is he is not eating the algae from the tank. Has not been eating for quite a while (a couple of weeks) We thought he was eating excess fish food so we have cut that back and he is still as large, maybe getting larger but not eating the algae. Could he have a blockage? <Yes> We had a clown Pleco that ended up doing this too, getting bigger but not eating algae till we found him dead. <Mmm, what sorts of food/s are you feeding?> Do you suspect constipation? I tried peas but he hasn't eaten them at all. Bacterial infection? <Possibly> What do I use. One guy suggested Epsom salts, <I do too... safe, often effective... readily available> what levels in what amount of water. <Posted: http://www.wetwebmedia.com/FWSubWebIndex/saltusefaqs.htm> I can move him to an alternative tank to set up a hospital tank. thanks for your help P. Carty <This fish may also be developing eggs... perhaps be egg-bound... I would try the Epsom per WWM. Bob Fenner>
Re: bloated Oto 03/23/07 As per the web page I will put an additional 1/2 teaspoon of Epsom salts to my 10 gal tank (I added 1/2 teaspoon yesterday). Some additional information that may or may not bear on this issue. I bought test kits yesterday and did testing of Nitrates and KH hardness. Nitrates are at 80ppm and hardness at 10. <Yeeikes, both high...> I have started 15% daily water changes with Reverse Osmosis water. My goal is to reduce nitrates to 20 or lower and hardness to 7 (as per pamphlet that says tetras like it around 7. <Ah, good> Would these two high values have any bearing on the bloating of the Oto? <Oh yes... of a certainty> You had asked what kind of food I was feeding them when I mentioned our late Clown Pleco. We are feeding TetraMin tropical flakes. <Mmm, I would augment this with either some other prepared food/s or give them a "treat" of some frozen/defrosted meaty foods at least once a week> Thanks again for your advice. <Welcome! Bob Fenner>

Otocinclus with bloodworm stuck in mouth -- 1/2/08 Hello, <Lydia> We are pretty new at this. One of our Otos has a bloodworm in his mouth which he appears to be trying to spit out without success. It keeps popping partially out of his mouth, but he does not or is not able to completely eject it. Nor has he swallowed it. This is the first time I have ever seen an oto with a bloodworm, although doing a search it appears they sometimes eat them. Is he likely to eventually swallow it or should we attempt to extract it? <Leave it as is... more potential harm in trying to remove> I really fear doing more harm than good. <Agreed> Other than what looks like attempts at spitting out the worm he is acting fairly normal still. It is not always hanging out - it disappears in his mouth and then he seems to try to spit again and part of it comes out for a little before disappearing again. It has been about an hour or a bit more. We appreciate any suggestions on whether we should try to gently catch him and pull it out (although I am not even sure we could get hold of the worm) or leave him alone. I tried calling the local fish store, but they are closed for the holiday. Thank you! - Lydia <Many fishes have "rear pointed" folds, other mechanisms to direct foods/prey downward into the gullet... once swallowed to some extent... only one way to go... I would feed your fish/es more fine/chopped foods. Bob Fenner>

Re: All is well - was Otocinclus with bloodworm stuck in mouth -- 1/2/08 Hello again, <Howdy> We successfully extracted it, which went surprisingly easily. He is back in his home and hopefully none the worse for the wear. Thank you! Lydia <Thank you for this follow-up. BobF>

Oto Quarantine Question (RMF please comment/correct) 12/29/07 Hi Crew! Happy Holidays to you! <Thanks!> I have some Otocinclus and Corys in quarantine. I got them the day before yesterday and all have been acclimated into the quarantine tank and seem to be doing fine. I have some driftwood in the quarantine tank with them. <Good. Also remember they need MASSES of oxygen, and will often suffocate under less than perfect aquarium conditions. These are fish of very shallow, fast-moving streams.> I have lightly fed frozen bloodworms (the Corys ate them, I didn't see the Otos eat these) and Ocean Nutrition Formula One flakes (I saw one of the Otos nibble on these). Today I am going to blanch some zucchini for the Otos. <Hmm... Otocinclus are really pretty much green aufwuchs/algae eaters in the wild, taking in the algae and the tiny animals hidden among it. In captivity they can be tricky to feed without healthy growths of green algae. Do try prepared alternatives such as crushed tinned peas, Sushi Nori, algae wafers, etc. But the best is nice lumps of green algae grabbed out of a clean pond. The lifespan of Otocinclus in tanks with no/little green algae is very poor. Brown algae, blue-green algae, red algae (hair algae), etc. are not substitutes! It has to be GREEN algae, the fuzzy leaf-green stuff that grows in clean, brightly illuminated tanks.> I've been reading WetWebMedia (love your site!) and saw that Otos can be a host to a number of parasites. While in quarantine, should I give them medicated food for parasites and or Treat with Fluke-Tabs for parasitic worms? If so, what type of food? I'm not really sure if the Otos will eat it. <Your main problem is diet: in my opinion the majority of Otocinclus starve to death, and if parasites are an issue, it's mostly after they've been starved into a state of weakness. So your quarantining is as much about fattening them up as fixing any parasites. In any case, getting these fish to eat medicated food will be tricky, so the simpler option will be to add something to the water, such as Fluke Tabs. That said, Otocinclus are peculiarly sensitive to chemicals in the water, and I'd tend to treat them only if there were signs of ill-health, or at least no signs they were fattening up. RMF may disagree/have alternative thoughts.><<I do not. Commercial importers might do this... to benefit, but most imported members of the genus are so "beat", starved, that it's best to not quarantine them at all... but introduce directly to the main/display and get feeding ASAP. RMF>> If I should treat the Otos, should I do while the Corys are in the tank, or after they have been moved into the main tank? <I'd do them together, if required.> Thanks for your answer, and for this wonderful site! Happy New Year. Michelle <Cheers, Neale.>

Otocinclus With Parasites -- 10/09/07 Hello crew, My Otocinclus looks very sick. A light yellowish lump in his mouth appeared yesterday, now there's more lumps; and his breathing is a bit slower. Otherwise he's acting pretty normal, still active and trying to eat up algae; his color also looks fine except for 2-3 white dots that are possibly ick. I've attached a picture of his sucker mouth. I had water condition problems a couple months ago, my tank was about 1 month old then. It's now about 3 months old; I was able to keep water conditions good since I had the previous problems: which were high ammonia, pH dropped. Unfortunately though, two days ago, I did a 25% water change, and probably scrubbed the pump/filter assembly a little too fervently, so the ammonia went up slightly; probably got rid of too much good bacteria? I used some ammo lock to decrease the toxicity level, and have been doing partial water changes daily to stabilize the ammonia level. I only have two fish in the tank currently, and the other fish looks fine so far. I looked on your site, and some fish disease information online, but I can't seem to figure out what the lumps are. Any tips what I should do? Thanks so much for all your help; you guys had great advice for me the times I've written so far!-Vanessa < These little sucker mouth catfish come from warm soft acidic waters of the Amazon basin. They are wild caught and can be a host to a number of parasites. Treat with Fluke-Tabs for parasitic worms and try to maintain good water quality to prevent further stress on your fish.-Chuck>

Unidentified Otocinclus illness 7/6/07 Hello all, I am new to posting on WWM, but I have found your site to be very informative. It has helped me better understand my tank and helped me prevent more than a few problems from happening. <Am very glad for this aiding> I have a 29 gallon freshwater, planted tank that is just under 6 months old. The tank has been cycled for approximately 3 months with ammonia and nitrite steadily at zero. The nitrate vacillates between 5 and 10 ppm. My pH is about 7.5 (I use tap water which has a pH of about 8.2 and I use a Neutral buffer, but 7.5 is as low as it goes; I also use driftwood in the water, but my pH is still around 7.5).I do 25% water changes on a weekly basis. The tank has both fish and shrimp. There are 5 zebra Danios, 4 dwarf neon rainbowfish (2 male, 2 female), one young Bushynose Pleco, a 2" SAE (which I am working on removing from the tank), <Are not easy to catch!> a pair of orange platies, a pair of honey dwarf Gouramis, 1 bumble bee goby, <Mmm, actually more of a brackish organism> 2 Otos that are gray/black and 1 Oto (labeled by the LFS as an "Oto niger") that is brown. In terms of shrimp, I have 5 red shrimp, 4 Amanos, and 1 green shrimp (that has changed color to a deep red). I do not have a CO2 set up (much to the dismay of many of my fellow planted tank enthusiasts). <Mmm, okay> I have had the Otos for nearly 5 months and one died unexpectedly (that is no sign of illness, discoloration, strange behavior) about three weeks ago. This happened to be the day after I introduced the Oto niger. <Mmmm> I was shocked since the Otos are always so active. However, now I have noticed that one of my gray/black Otos has some discoloration. The only way I can describe it is that it looks like it is wearing a yarmulke/skull cap. <I see this> It is a clearish sort of circle on the top of its head. I have attached a photo for you to review. The fish seems much more lethargic than usual (and than its fellow Otos) and I am not sure what sort of illness it is or if/how I can save this fish. I posted something on my planted aquarium web group and one woman said she had the same problem, but no idea why or how to deal with it. Her Oto just died from whatever this is. I am hoping I won't have to lose another fish. I look forward to your reply. Any advice you could offer would be great. Brian (in SF) <This marking appears at times from animals that have been damaged in shipping (their heads rubbed repeatedly by others in the bag)... and by negative interaction with other Loricariids... I would keep a sharp eye out to see if the Bushynose of congeneric (other Otocinclus species) is working this fish woe. No "treatment" other than separation is recommended. Bob Fenner>

Re: Unidentified Otocinclus illness (follow-up) 7/7/07 Hey Bob (and others), <<You've got one of the 'others' this trip, Brian. Tom with you this time.>> Wow! Thanks for the reply! You hit the nail right on the head with the other Loricariids. <<Bob's pretty good at hitting the nail on the head, Brian.>> About three hours after I posted this, my Bushynose Pleco was trying to devour the Oto. The Oto was actually still alive and I managed to startle the Bushynose Pleco off. The Oto swam away. However, the Oto was clearly wounded because about 10 minutes later one of my Amanos had the poor fish by its tail and was trying to drag it around the tank. I tried isolating the Oto, but it appeared to be dead - no movement, discoloration, etc. Of course, I went to dispose of it in the toilet and it started to move again. However, I figured once I had exposed it to the untreated water (chloramine) of the toilet there was no coming back. <<A bad day all around for that poor, little guy.>> Is the only way to prevent this from happening again (my other two Otos are colored just fine) to make sure that I choose an Oto with deep color to begin with? <<Not necessarily, Brian. Otos are often transported in groups of mixed species. In fact, what might be marketed as an 'Otocinclus' could very well be one of the 'Parotocinclus' species, some of which are more of a light brown (to keep it simple) in color. The so-called Golden Oto is one of these. As a small bit of trivia, a true Otocinclus does not have an adipose fin -- a small fin along the back between the dorsal and caudal (tail) fins. An adipose fin on an 'Oto' marks it as a Paraotocinclus. (If you're intent on boring someone to tears, share this with them. :) )>> The LFS from which I bought the Otos described them as high-risk fish (always!) due to the cyanide that is often used to catch them in the wild and the stress of transport. However, I figured after 3-4 months of living in a tank with good water quality that I was home free. I guess I was wrong. <<Cyanide harvesting is a valid cause but transport stress is probably more likely the culprit in the early deaths of these fish. Otos (to keep it 'generic') can't digest algae (cellulose). Rather they have anaerobic bacteria in their guts that do the work and the fish is 'nourished' off of the by-products of this process. During transport, so much of the bacteria may die off from lack of food that, even when the Oto is placed back into an algae-rich environment, the fish literally starves to death, i.e. the algae passes through the fish's system untouched, so to speak. Now, the biology lesson notwithstanding, one of the best methods of selecting a healthy Oto is to find a 'fat' one and only select specimens that have spent at least a couple of weeks at the LFS. If the fish's stomach is flat or concave, pass it by. The prospects for a skinny Oto's long-term survival are not good at all.>> Two clarifications to Bob's "mmms". I brought up the lack of CO2 setup, but neglected to say that I regularly use Flourish Excel (liquid CO2). <<Not 'splitting hairs' here, Brian, but the Excel product isn't 'liquid CO2' though it does supplement the tank with carbon, as does CO2, but rather from organic matter. (Guess that did sound like I was splitting hairs, didn't it? :) )>> Second, regarding the bumble bee gobies as brackish water species. I had read this and had crossed them off my original stocking list for that reason. However, a LFS which only carries freshwater fish (or at least only has freshwater tanks) raved about the success they have with this particular bumble bee goby in fresh water. Despite its picky eating (which seems to be common for this fish), it seems to be getting along just fine. <<I would share the same concerns that Bob, no doubt, has with regard to this animal, Brian. An LFS's short-term success with keeping a brackish species in FW doesn't equate to long-term success for you or your pet. Very often, brackish water species start out in FW but must make the transition as they mature in order to thrive/survive. Time will tell, of course, but it's best to keep an eye out for otherwise unexplained problems should they arise.>> Again, many thanks for your wisdom and your willingness to share it. <<More than happy to help, Brian. Good luck and best regards.>> <<Tom>>

Oto loses colour Hi, We have a sick Oto which has suddenly lost its pigmentation and is looking a sickly grey. It is swims weakly, sometimes floating at the surface and drifting in the current. Otherwise its body, fins, etc. look in good condition. Can you suggest any remedy or is this something to do with the tank conditions? We have a 180-litre (40 gallon) community tank with 9 guppies, 3 minnows, a Pleco and 5 Otos altogether. It has some live and plastic plants, a couple of logs and a small rock pile (slate), i.e. there is a relatively large surface area available for the Otos to graze on. It has been set up for about 3 months, but, about 3 weeks ago, we had problems with water quality, fungus and white spot. These were successfully treated with 10% water changes every day and ESHA 2000 and EXIT. Treatment finished 7 days ago. Current conditions pH = 7.8, KH = 6°, GH = 12°. Ammonia, nitrite and nitrate levels all low. We have isolated the sick Oto. Grateful for your advice. Regards, Quentin <Hello Quentin. Let me start by making a general statement about Otocinclus: they are extremely difficult to maintain, and the vast majority die soon after import. The problem is that they feed on really only a single thing -- aufwuchs, a combination of green (and exclusively green!) algae together with the tiny invertebrates that live within that green algae 'biofilm'. Unless you have an established aquarium of large size with very strong lighting (2+ watts per gallon) so that green algae can flourish, it is exceedingly unlikely your Otocinclus will be getting enough to eat. How many months it is before they die is variable, but starve they will unless ample substitutes are provided. Algae wafers can work, but Otocinclus find it difficult to compete with other fish, and the fact you have other algae-eaters, specifically guppies and Plecs, makes this point critical. For this reason, I simply don't recommend them as community fish. Furthermore, while water chemistry itself isn't all that important, temperature and water quality are very important. Most people keep their tanks far too warm for Otocinclus, which come from cool, fast-flowing streams and want something in the 20-25 degrees C range rather than the usual 24-28 degrees C most people maintain standard community tropicals at. In other words, a near-subtropical, fast-water tank with things like White Cloud Mountain Minnows and Danios is much closer to what they want than a standard Amazon community aquarium. You also mention ammonia and nitrite levels as being "low" -- but be under no illusions here, Otocinclus MUST have zero levels of both. If you can detect either in your tank, it is simply not suitable for Otocinclus. In all likelihood the sickly specimen will be dead within a few days, so treatment here is irrelevant. Optimizing water quality, lowering water temperature, providing ample green algae and suitable invertebrates would all be things you could do to help the isolated fish, but that's about it. For the rest, you need to ensure your aquarium satisfies the demands outlined above. Hope this helps, Neale.>

Re: Oto loses colour 7/6/08 Neale, Many thanks for your helpful advice. The Oto has now died, sadly. However, we will develop the tank environment to make it better suited to Otocinclus. They are an entertaining fish to watch. <Yes they are. In the right tank, they can be great fun. In the wrong tank though... My most recent run-in with this species was a disaster, some of the Otocinclus deciding to graze on the mucous of some large benthic gobies. They have a reputation for attacking big, slow moving fish such as Discus and Angelfish. On the other hand, aquarists like Takashi Amano make much use of Otocinclus in planted aquaria, usually alongside Caridina shrimps as a superb combination for green algae control in brightly lit aquaria.> Thanks again. Your website is a mine of information and a great support to the budding enthusiasts in our family. Regards, Quentin <We're happy to help, and thanks for the kind words. Cheers, Neale.>

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