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FAQs on Otocinclus Foods/Feeding/Nutrition

Related Articles: OtocinclusLoricariids

Related Catfish FAQs: Otocinclus 1, Otocinclus 2, & FAQs on: Otocinclus Identification, Otocinclus Behavior, Otocinclus Compatibility, Otocinclus Selection, Otocinclus Systems, Otocinclus Health, 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 catfish feeding around platy fish and bladder snails?       12/5/14
I have a tank rated for 29 gallons by the manufacturer. The tank is 36" L x 12" W x 18" H. The ph is 8 and nitrates and ammonia at 0. My filter is a sponge filter rated for 40 gallons. This tank contains 2 guppy females, 5 neon tetras, 10 platy fish, 1 Otocinclus catfish,
<These are social; but a few more please. For sure they often seem to die a few days after purchase because they're half-starved by retailers. So buy yours carefully, from a tank where they're eating, and to be on the safe side, get a fair number to allow for mortality. Maybe 5-6? The cost, what, a couple of quid each, so this isn't asking you to throw money away.>
and numerous bladder snails.
One of the platies is a week old baby. It is a female, I think. I am temporarily keeping it in a breeding trap until she is big enough not to be considered food in the main tank. I feed her Hikari First Bites and Hikari tropical micro pellets.
My platies are 5 males and 5 females, counting the baby. They seem fairly active, but not aggressive. The platies and bladder snails eat everything that is not a live fish!
<Quite so. Algae is a major part of the diet of both species, alongside organic detritus. This isn't a bad thing then, seeing them graze.>
The algae in my tank, tetra tropical flakes, Hikari tropical micro pellets, algae wafers, and peas.
My question here is will the Otocinclus get its fair share of food? If not, what should I do to ensure it does get its fair share?
<A good question. Otocinclus feed primarily on diatoms and green algae.
Strong lighting helps develop these. They don't eat detritus and they don't eat brush/hair algae. They will graze on algae wafers, and also on very small meaty foods (frozen lobster eggs for example). If you have real trouble keeping Otocinclus fat and happy, I'd suggest skipping them in favour of the much tougher and more omnivorous algae-eater Ancistrus.>
Thank you.
<Cheers, Neale.>
re: Otocinclus catfish feeding around platy fish and bladder snails?       12/5/14

Thank you Neale! :) one more question. I caught yet another baby in my tank today. Looks like it is another female platy, I think. Picture of her and her sister provided.
<That photo is almost as small as a newborn Platy...>
Do I have room to keep the new platy too in my tank?
<Probably. I can't remember how big your tank was. 30 gallons? That would be ample for a dozen Platies and a school of Otocinclus.>
Thank you.
<Most welcome.>

re: Otocinclus catfish feeding around platy fish and bladder snails?     12/7/14
Thank you Neale! :)
<Most welcome.>

Re: Got my new plants    6/8/14
I decided to go with Otos as they are smaller and less aggressive. I brought 10 of them for my tank. My tank is well established been set up for almost a year now... but only got live plants and plant light last month.
all water parameters read good and i hear they are real good when it comes to eating algae. all seem veraciously hungry and are eating the algae what can i give them after the algae runs out
<Algae wafers. Otocinclus starve quickly; supplement their diet immediately, offering algae wafers 2-3 times per week as appropriate, ensuring that all your Otocinclus have nice round bellies. New specimens
can be very delicate, and any specimens that are hollow-bellied now are unlikely to survive for long without immediate fattening up.>
thanks Alex.
<Cheers, Neale.>

Different types of algae and who eats/needs them?  (for miniature Otos)     8/26/13
Hi Neale, I hope you're enjoying your weekend! 
<Did indeed.>
I've attached 2 close up photos of some algae growing in 2 of my tanks. 
Since you've been keeping fish a long while, do you know what fish eats what type of algae....?
<In my experience, the "fish eats algae" paradigm is only of limited use, and tends to depend a lot on what other foods are available to the fishes in question. That said...>
In particular, do my algaes in these 2 pictures look like the type the tiny 1.5 inch Otos like to eat?
<Otocinclus tend to eat green algae and diatoms. Green algae is usually leaf-coloured and forms patches or low fuzzy tufts in aquaria. Diatoms form the golden-brown slime on glass and rocks. The dark green to blue-black beard and thread types are usually red algae (red is the colour when preserved in alcohol, by the way) and Otocinclus generally don't eat these types.>
Most store tanks are low on algae and therefore they just feed them pellets which is less ideal.
<Not sure this is strictly true; good quality algae flakes and wafers should make an acceptable staple.>
Since I grew some naturally with great success on this rock and the crypts plants, I wonder if I have an Oto buffet, or would they ignore it and grow feeble without some other food?
<Try it and see!>
I'm asking because in the forums I have heard people saying this fish eats this algae but not that algae, and they go on and on about their specific types of algae and the types that will or will not get eaten by various types of fish!!!
<Correct. There's some overlap between algae eaters, but each fish species often has preferences. I'd also add that few, if any, fish is as good as Nerite snails. Fish simply aren't as methodical. Fish generally ignore the thread or beard algae types too, with a few exceptions (Siamese Algae Eater and Ameca splendens spring to mind).>
I'd love to try a small school of Otos, but I want to make sure I have the right type of algae so they're not just stuck with compressed tablets of algae.
<Do bear in mind that Otocinclus aren't just eating algae; to a large extent they're feeding on detritus and tiny animals that live among algae threads, what scientists call "aufwuchs". So, even if the algae type isn't 100% right, it'll still be home to stuff Otocinclus can eat.>
Every fish care paper I read says "it's best to have natural algae growing in their tank," but that's not specific as to what type the species actually prefers and will eat.  I suspect what I have is good Oto food....but don't know for absolute certainty if these are super picky little creatures.
<They're semi-picky. They are at risk of starving in a new aquarium or one with dim lighting and hence little algae growth beyond, say, blue-green algae (which they cannot eat). But in a mature aquarium or one with enough lighting for plants to thrive, they'll find enough to eat, especially if their diet is supplemented with a good quality algae wafer. Generally, competition from other fish tends to be the killer. If they're harassed by larger fish, then they'll fail to thrive, no matter what other factors are correct.>
If I move the sword(or swap rocks) to the 2nd tank, they could have the rock with the heaviest algae, since there will be more of them.  Though they're so little... Not sure even they could make a dent on the furry rock any more than the sword has.  Of course maybe if they had just the plants and the less algaeful rock, maybe they'd clean those up faster.  That would be nice for the plants.
And the sword favors the rock.  She munches it happily.....I feel a little guilty to move it to the other tank.  Is the algae on the rock probably the same type as the algae growing on the plants anyway?!
<Otocinclus and livebearers enjoy the same algae types, so whatever the Swordtail eats will be correct for the Otocinclus.>
And....would I need to supplement the Otos diet with anything else if this is the right type of algae for them?
<For sure, though less often (once a week, perhaps) if they are nicely fattened up on algae and detritus.>
I do intend to put a piece of driftwood in their tank as well, as I heard they like it.
<Correct, though likely this has more to do with culturing algae and aufwuchs than anything else.>
Thank you, I hope you've kept Otos to know what they like too.
<Yes, have kept them, though much prefer Nerites as algae-eaters.>
I know you like brackish a lot, which they're not, but I think you have wide knowledge and experience.
<Cheers, Neale.>

Re: Different types of algae and who eats/needs them?  (for miniature Otos)     8/26/13
Thank you, Neale, very helpful.
I like the little Otos and I'll get some. Have a nice week.
<Most welcome! Neale.>

Guppy stocking; Otocinclus feeding  10/16/11
two topics that I have been wondering about.
- - - guppies - - -
I've been reading the articles and FAQs about guppies with great interest.
I have noticed that you have quite strong opinions about acceptable stocking levels and water temperatures. Are you aware of the story "Killing them with kindness" by Anthony Fischinger?
<Not aware of it, but have read it now.>
Apparently, many fancy guppy strains are sensitive due to inbreeding,
but within a couple of generations of selecting for hardiness,
<"Selecting for hardiness" is essentially letting some of them die, and breeding those that remain. By definition, that means you're providing the fancy Guppies with less than ideal conditions by their standards, and not worrying about the weaker ones getting stressed and suffering. Hardly a humane way of keeping fish. I do agree with the author that crossbreeding fancy Guppies quickly returns their offspring to the vitality seen in wild Guppies -- that's been demonstrated under laboratory conditions and needn't be tested by aquarists. But most casual aquarists within the hobby won't want a bunch of wild-type Guppies without a particular colour scheme; what they want are Red Cobras, Snakeskin, or whatever Guppies.>
they can thrive at stocking levels up to 20 guppies per gallon,
<Absolute rubbish. Or rather, you can keep any fish at very high stocking density, but assuming you keep ammonia and nitrite at zero, and nitrate at some low value, less than 50 mg/l for Guppies, and less than 20 mg/l for cichlids. Doing this would be incredibly hard work for a casual aquarist, and nine times out of ten, trying would do nothing more than expose your Guppies to such poor conditions they'd sicken or die.>
rare water changes (in a planted aquarium), and wide temperature swings.
Could you comment on this story?
<Gladly. What that aquarist is saying is that if you cull some of your weaker Guppies, ignore low levels of damage to the fins, and repeatedly medicate your Guppies, you can keep them in poor conditions. Well, he may well be right, and certainly "the wild" isn't a nice place, and if you replicate some of the hardships in the wild, and let your Guppies strains crossbreed, then the over a year or two you will end up with wild-type Guppies able to put up with the same sort of hardships that wild Guppies have to deal with. But here's the thing: wild Guppies only live a few months, particularly the males, and their colours are nothing like the ones casual aquarists expect to keep in their aquaria. From an academic point of view this article is interesting, and I dare say that over a beer or two, the author and I would have quite a good conversation discussing the pros and cons of this approach. But as a guide to keeping store-bought fancy Guppies, it's of no value whatsoever. The author is absolutely right that fancy Guppies aren't as easy to keep as their wild kin, and that breeding and selection for certain genes have much to do with that, but that's not the same thing as saying the best way to keep store-bought Guppies is to expose them to the same harsh conditions their wild ancestors could tolerate.>
Would it really be a bad idea to let a guppy tank get crowded over time?
I've also seen local pet stores carrying guppies at very high stocking levels. They seem healthy, although I don't know whether the shopkeeper is removing sick fish all the time.
<Pet stores buy in farmed Guppies, and all the ones sold, except perhaps the "feeder" ones, are purebred strains. As such, they'll be true fancy Guppies with the same weaknesses as all fancy Guppies. Just because your local pet shop has Guppies maintained under what might be poor conditions, doesn't mean that pet store has bred their own hardy Guppies! On the contrary, even the best pet stores buy Guppies assuming to sell them quickly, and will probably expect a certain level of mortality within the group bought.>
- - - Otocinclus - - -
I have two small Otocinclus (probably o. vittatus, 2 cm, 3/4 inch long excluding caudal fin) together with three (3 cm) guppies in a 30 L tank with gravel and plants (hornwort, elodea, java moss, Anubias). Water parameters: 24-25 C, NO2 0 ppm, NO3 <20 ppm, GH 10 dH, KH 4, pH 7.0. The NO3 level is a bit high for Otos (color of the test strips for NO3 is a bit hard to match to the reference scale), but seems to be rather stubborn even with weekly 25% water changes. (The tap water here reads about 10 ppm NO3.)
Anyway, here is my real question: how can I tell whether the Otos need supplemental feeding?
<Look at their bellies; starving Otocinclus are distinctively hollow-bellied, and often look thin overall, too, and may have sunken eyes and exaggerated, jerky swimming movements as well.>
When I got them (1 month ago), the glass and Anubias were covered in brown algae. They devoured them: in two days, the plants were green again and the glass panes were crystal clear. Since I read at WMW and elsewhere that this tank is way too small to sustain Otos by natural algae growth, I offer the Otos a piece of zucchini every couple of days, which seems to disappear in a night or two. The problem is: the front window gets covered in various types of algae (green dusty film and greyish "ink stains"; all easily removed with a plastic scraper) and they don't seem to eat those algae even after four days without supplemental food. The Otos seem to have round bellies. Could it be that somehow this tank has more algae growth than two Otos can consume? Is it the wrong type of algae?
<Could be either, or both! Otocinclus feed primarily on green algae, and secondarily take some diatoms. In the wild green algae and micro-invertebrates ("aufwuchs") are their prime food sources. They don't eat red algae (e.g., brush algae) or blue-green algae, and may ignore diatoms if other foods are available. In any event, to think of them as pure herbivores is wrong; their diet is mixed, with some algae and some micro-invertebrates, and you need to plan accordingly. Actually, in a well-maintained aquarium they'll often do well on scraps of fish food that they find alongside green algae, so provided they look healthy, there's no reason to worry too much.>
<Cheers, Neale.>
Re: Guppy stocking; Otocinclus feeding    10/18/11

Hi Neale or other crew member,
Thank you for your extensive reply. One remark though, because I feel that there is a misunderstanding about what the author was advocating.
WWM wrote:
"I do agree with the author that crossbreeding fancy Guppies quickly returns their offspring to the vitality seen in wild Guppies -- that's been demonstrated under laboratory conditions and needn't be tested by aquarists. But most casual aquarists within the hobby won't want a bunch of wild-type Guppies without a particular colour scheme; what they want are Red Cobras, Snakeskin, or whatever Guppies."
As far as I understand from Fischinger's article -- and his friend Greg who also has some articles on that website -- they do actually breed them as fancy guppies, including presenting them on guppy shows. The difference is that they cull based on both appearance and vitality, rather than for appearance only. For example, Greg writes on http://www.fancyguppies.co.uk/page79.htm about his Green Lace Snake Skin guppies that are thriving and producing fry at temperatures down to about 60 °F (16 °C).
<I do thank you for this correction, clarification. 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.>

Re: Angelfish Compatability Question, now, Algae issues... Otos chatting    1/17/10
Okay, okay, the whole city only has 1 PetSmart, and they said they were never going to get angels. And my parents got 6 Otos. Totally surprised and overwhelmed, I knew they liked algae and need zucchini? Help?
<Unless that particular PetSmart has something against Angels, I have to think that the person you spoke with may not have known what the store was going to get. Any and all of the major chains that I've been to have carried Angelfish! As for the Otos, take the time to use WWM to read up on their needs.... can be difficult fish to keep alive for an extended period of time, due to dietary needs.
Re: Angelfish Compatability Question, now, Algae issues
Thanks... Now that I've sort of calmed down... Okay, there are 6 Otos. 4 medium size, 1 tiny, and 1 huge. What do I need to feed them? I know about that they need algae wafers only if the algae run out. And spinach?
Lettuce? Driftwood? By the way, The PetSmart said they die too quickly. The last time I ever saw angels there, it was one very very lonely and bored one. Aw well, thanks for your help! Even if the topics change once every two emails... Sorry about that! Otos seem to be very spirited....
<Please read where I referred you for information on feeding/care/etc. I scanned the pages prior to linking you to them -- I know this information is there! Understand that these fish, like most fish, do not eat ALL algae, but a specific type. You will likely need to supplement their feeding to have any hope of them surviving. Please read, read, read. Here are those links, again:
Don't forget to check out the linked pages at the top of these pages, as well.
Re: Angelfish Compatability Question, now, Algae issues, now, Oto care/feeding
Thanks! Sorry for the bad spelling. Looks like I got to steal veggies and get algae wafers... Sadly they only eat green algae.... Though I do have some. Thanks for the great help you've given me!
<Do see if you can locate a wet-frozen Spirulina cube-type product, as it might help, or, if you have an ethnic foods section in your grocery store, check out the Sushi Nori that is sold for human consumption with the Oriental foods... either of these are products that stay "good" for a long time, unlike zucchini, and so would be easier to have on hand. Also, do find out what's going on with your filter -- the turnover -- as there's a good chance that filtration needs to be upgraded as you add fish. You're welcome!
Re: Angelfish Compatability Question, now, Algae issues, now, Oto care/feeding
Even though I'm Asian I still ask this.... Won't Nori have salt, and something like sugar or stuff that kills fish?
<It shouldn't... is just dried seaweed.>
I've learned that human foods aren't right for fish...... Am I right?
<Well, when you keep fish who have special dietary needs, then you feed whatever they'll eat that satisfies those needs! I am not saying to feed them hotdogs (you'd be surprised how many people feed foods such as this!), but Nori is about as close as you're going to get to the natural diet, along with the Spirulina tablets, if they'll eat them, or wet-frozen Spirulina.>
I know that my current 6 Otos are grazing on algae right now. They still eat the brown stuff. The otofaqs said they only eat green algae?
<Blue-green algae comes in many colors, as do other types of algae... so just be glad that they're eating something! On the other hand, you've bought them to rid algae, but must now have a steady algae supply in order to feed them, so think about that and factor it in... I know you were doing shorter photoperiods, but you may have to go back to the old way in order to grow the algae for them.>
Thanks again! You must be a very pro fishkeeper to answer my questions.............
<You're welcome. As for "pro," I assure you I am not! The great thing about this hobby is once you learn the ins-and-outs of something, no matter how small it is, you can share that information with others and put it to use in your own aquaria. There's a lot I don't know, but I have a feeling I mumble my spiel about the nitrogen cycle in my sleep, and that information helps plenty of folks, all on its own. In the meantime, I keep learning! Glad to be of help!
Re: Angelfish Compatability Question, now, Algae issues, now, Oto care/feeding
Wow...so fish CAN eat dried seaweed. But not hot dogs... okay, I will get some seaweed.
<Sounds good.>
One of my favorite foods... oh, and I didn't buy them to rid of algae... my parents bought them to think they are so cute and that I could take care of any fish. Soon they might bring home a chocolate gouramis or a Moorish Idol... anyway... so now I should turn the light on 12 hours a day to grow the algae. Hope its enough... because those little fishes already cleaned an Amazon sword leaf 30 min after they were introduced....
Soon I'm going to have to raid the refrigerator for veggies. Have you ever kept any of these? Online it says that Otos mainly die of starvation or the stress of transport. Mine were already selecting which leaf their going to attack next. But starvation... (how long will the food last?)
<You'll just have to keep an eye on them. Depending on how long they were in the store, they're probably pretty hungry and are sort of having a feeding frenzy right now! Their eating may slow down. Just keep an eye on their tummies -- as long as they are rounded, and not concave, you're doing good.>
Random Question: Do Otos need driftwood? and can you obtain driftwood from a tree or pond?
<No, they don't need it -- don't eat it the way other catfishes do. You could obtain it from nature, but I prefer to buy mine from the pet store.
Malaysian driftwood sinks automatically, and it's nice and clean, and doesn't require any other steps to prepare for the tank. Be careful with driftwood, as it can make the water more acidic.>
Thanks... I think anyone's a expert at fishkeeping when they know information... I was going to stop asking you questions that you probably answered 200 times already for others... but... then came the Otos.
<No problem.>
P.S. has anyone asked you: My Bettas sitting at the bottom of the bowl!
<Surely you know the answer to this, if you read the dailies even infrequently! The answer to this question lies in the question itself...
Re: Angelfish Compatability Question, now, Algae issues, now, Oto care/feeding. Refer this child to the chatforum
Hmm.... thanks. and I don't own a Betta. Just asking an annoying question my friend asked me. I do know though...(I hope) Thanks, I had a panic attack when I saw all of the descriptions of Otos being easy to kill... and all of the stuff about they only eat one type of algae... looks like they are just these little fishes that are a bit demanding... and a bit funny to watch.
My entire family is staring at them right now.
<Haha it's the new t.v.!>
Thanks for your patience and help! Have you ever kept Otos? I never know anybody that has tried...
<I have not kept these fish. I tend to shy away from the fishes that are considered hard to keep because I have so many fish that it would be difficult to care for one with special dietary needs! However, I wish you the best of luck with those little guys. It sounds like you're on the right track!
Re: Angelfish Compatability Question, now, Algae issues, now, Oto care/feeding
Thank you! I hope to say that all 6 are alive and well years later! Hope they like the Vegetables I dump into the tank that I dont want to eat!
<Haha better than stuffing them in the sofa cushions or potted plants!>
I still have to remind to my parents that the TV is fragile and cant be touched... So, goodbye! May the fish gods be with you!
<Hmmm... fish gods... do they negate the need for water changes? Just kidding!
Driftwood is mandatory?
Dear crew...
you guys have a wonderful site that I have been finding answers for years however here is one I dont know about. I have 6 Otos in a 29 gal with 1 guppy and some Glowlights. However, do you need driftwood to supplement the
Otos diet or can flakes and algae, spinach do? If driftwood is needed, can you get it from the forest? Like finding a fallen branch, cleaning it, and putting it in the tank?
Thanks you very much! I hope that this is not a repeat question!
<Otocinclus do not eat bogwood, so no, it isn't mandatory. That said, like many Loricariids, they may consume small amounts of wood in the wild, and while they don't digest it, it may provide useful fibre. So if you want to
put a small bit in the tank, go ahead and do so. Collecting non-resinous wood (i.e., not pines, etc.) and putting them in aquaria has been done, but you have to be careful. Pesticide sprays are usually toxic to fish, so anything from a non-organic back garden is likely to be dangerous. It's best to collect wood from a wilderness of some sort far from agriculture and horticulture. But do remember that fresh wood contains lots of organic matter, and it WILL rot underwater. This places an additional strain on your filter, and though it won't much affect water quality, you will find fresh wood sprouts fungi and produces lots of solid waste particles that collect in the filter floss. Cheers, Neale.>

Re: Angelfish Compatability Question, now, Algae issues, now, Oto care/feeding  -- 1/21/10
Okay... I think the Otos made it past the first hurdle. {The first week}
But the algae is running out fast, what I thought would be an unbeatable amount of algae is already reduced to half. FOR SOME REASON, THE ALGAE ISN'T GROWING BACK! No Nori or wafers yet, parents haven't gone to the market yet... how do you get them to eat blanched zucchini? the kind boiled in water?
<Whenever I feed veggies, I rubber-band the veggie to a rock and let it sink. Some veggies sink; some don't, but using the rubber band and rock ensures that you can easily find the remains (if there are any) and remove them. Stores also sell veggie clips, but I like the rock better, because it is cheaper and doesn't limit the size of the vegetable piece (as long as you can fit the rubber band around the rock and the veggie, you're good to go!>
Thanks Melinda,
<You're welcome!>
this is sort of scaring me how much they eat, and how much they poop.
<Have you been able to figure out the turnover rate on that filter yet? Be sure and test regularly for Ammonia and Nitrite to make sure that their bioload isn't stressing your biological filter, and test Nitrate to make sure that you're compensating for the new guys with enough water changes to keep Nitrate below 20. Good to hear these guys are still doing well!

Re: Angelfish Compatability Question, now, Algae issues, now, Oto care/feeding 1/24/10
Hello again! I'm replying again...
<Hi! It's Melinda!>
Dumb kid question of the day: for Co2 in the water, can I blow air into a straw that is in the water? lol.
<Why do you think you're needing CO2? Let's start there. There are some cheap CO2 setups involving yeast, but read here on a CO2 setup like you're imagining:
However, I'd start with "Why?" and work my way up to the system itself.
For the size tank you have, there are some pretty cheap systems available (check out Red Sea systems).>
BTW, how do you grow algae?
<Well, you used to have the method down, no question! Sorry, I don't mean to joke. The problem is that they're eating it as fast as it's being produced. The methods are still the same, and you used to be able to grow plenty, too much, in fact, for your own tastes, but now, this is a different story.>
thanks, because my tanks almost out... and they still aren't smart enough to accept zucchini yet!
<"Smart" has nothing to do with it, really... this is a food that grows on land, that they've never seen before. Please refer back to earlier e-mails for links on feeding, or search on WWM for alternative feeding options. No fish eats everything, so it's important to continue trying. These fish were purchased with no prior research, and that's not their fault! You've got to keep trying. If these were fish your parents chose, as you indicated, then they should be the ones trying to provide for them. If this isn't possible, these fish can (hopefully) be returned to the store.
I understand where you're at, right now, because I've been in the position of telling people things they don't want to hear, even my own parents!
But, it's what is necessary, for these fish to survive. Please keep trying. It could be that the algae they are eating are enough to sustain them for the moment, and so they're not interested in anything else right now. As I said, keep an eye on their bellies. If they're concave, then they're not getting enough to eat.

Re: Angelfish Compatability Question, now, Algae issues, now, Oto care/feeding 1/25/2009
They sit around all day. the stomachs are round... but I'm worried that they dont eat the proffered food after the algae runs out. I guess the algae isn't out yet, so they aren't going to eat it. its like having a Big Mac in front of you while someone is trying to make u eat something else. lol.
<Right. While what they are used to eating is still available, they'll eat that. It can take a couple of days of no food to train a fish onto a new food, and that's not going on right now, because there's some algae left.>
I did do research, just was worried a bit, because I have never kept a delicate fish before.
<It's not one I would have recommended to you; however, you've got them now, and it sounds like you're doing your best to care for them.>
<You're welcome!

Green algae for Otocinclus catfish  9/29/08
Dear Crew,
I have had 3 Otocinclus catfish since May 2008. While they were being quarantined, they learned to eat zucchini, but they never took to algae wafers or Nori sheets. After their quarantine period, they moved to my 55 gallon tank, which has lots of brown algae and green spot algae. They are all very fat, very active after dark, and generally very healthy looking. I still feed them zucchini once or twice per week, but they never touch it. As far as I can tell, they are living off the algae in my tank.
<Certainly possibly in large aquaria, especially if they also consume small amounts of flake food and other "leftovers".>
I thought all was going well, until I came across the following information at your website (http://wetwebmedia.com/FWSubWebIndex/otofdgf.htm):
"Otocinclus really don't eat anything much besides green algae and the microorganisms therein. Brown algae, blue-green algae, etc. aren't substitutes! To get green algae growing, you'll need 2 Watts of light per gallon, at least. There needs to be a "turf" of green fuzzy algae on the plants and rocks. THAT'S what these little catfish eat."
So, I got worried that, despite their healthy appearance, my little Otos weren't getting adequate nutrition. (I've attached a photo, in case you want to see how they look.)
<If your Otocinclus have rounded bellies, then there's nothing to worry about.>
I read online about how some people "farm" algae for their Otos, and I decided to try it. I went to a local Koi pond and took some rocks covered in thick green algae. I put them in a plastic tub outside, in direct sunlight, along with some pieces of driftwood from the pet store. My plan is to get the algae growing on the driftwood, and then to exchange pieces between the tub outside and my tank, to keep my Otos supplied with at least one piece of algae-covered driftwood at all times. (I will wait a full six weeks before putting any driftwood in the tank, as a safety precaution against any parasites that might have come from the pond. I'm guessing that after six weeks with no fish host, any parasites will have died.)
<There's no need to quarantine bogwood or whatever left outdoors in water without fish. The main thing to take care is that excessive amounts of detritus don't get blown into the container. A few leaves won't matter either way, but anything that's been sprayed with pesticide for example would be potentially harmful.>
But, now that I've got everything place, I'm having second thoughts, which is why I'd like your advice. I tried to identify my pond algae online, and it looks like what people call green "hair" algae, and most people who have it in their tanks seem pretty upset about it. Apparently, it can really take over. So, I'm feeling a little nervous about putting something in my tank that everyone else seems to want to eradicate.
<You have a nice variety of algae there. The Moss Balls (actually algae) will collect bits of food and likely the Otocinclus will do some grazing on them quite happily.>
Now I only have about .65 WPG on my tank, and as the quote above says, I need 2 WPG to grow the algae, so I'm hoping that it won't thrive once I bring it in.
<The watts per gallon rule isn't hard-and-fast and does depend on various factors. In any case, take it for the guideline that it is, and if your Otocinclus are happy, that's all you need to worry about.>
It only needs to stick around long enough for the Otos to eat it. I'm attaching a photo of the algae to this email. Can you tell me, what kind of algae is this?
<Other than the Marimo Moss Balls, there seems to be some tufts of green algae on the bogwood.>
Is it the kind that Otos need?
And should I stick it in my tank?
As always, thank you for your expert advice!
<Cheers, Neale.>

Re: Green algae for Otocinclus catfish  9/29/08
Hi Neale,
Thanks for the info. Just one thing--you said, "Other than the Marimo Moss Balls, there seems to be some tufts of green algae on the bogwood." Those actually aren't Marimo Moss Balls. They're rocks covered in algae that I
fished out of a Koi pond.
<Ah, okay. All the same algae really, Cladophora (and related species).>
The driftwood is from the pet store, and the algae that's growing on it is what has transferred over from the rocks. But as long as you still say this algae will be good for my Otos, then I'll put it in the tank.
<It'll be good for them. Whether the algae will grow under poor light, I cannot be certain.>
Thanks again,
<Cheers, Neale.>

Otocinclus; diet   7/29/08 Hey guys sorry to bug you but I have a quick question that your article on Otocinclus did not entirely answer. Well the back story is that I wanted some Oto's for my 20 gallon tank that I will be setting up in my dorm room next month and wanted to get Oto's that I knew were healthy instead of gambling on some new ones. I waited a week after the pet store I work at got the Oto's in (stupid manager pet my babies in with bumblebee catfish) to avoid the initial die off. Then I purchased 2 yesterday and put them on one side of a 10 gallon tank (at last check the pH was 6.4 and the tank is planted with Amazon sword, moneywort, cardinal plant, and water sprite cuttings I snuck home from work) with a divider that is keeping the Oto's, 4 feeder guppies, a black Veiltail angelfish which will join the Oto's in the 20 gallon, a pair of golden rams, and a third ram the male did not breed with from the other side of the tank that has ram eggs in it (the parents ate the eggs once and I wasn't risking it again {one day left!}). <Ah, potential problem here: Mikrogeophagus ramirezi need very warm water to do well, something between 27-30 degrees C; your Otocinclus on the other hand can't bear water that warm, and will be substantially more short lived. They want something between 22-25 degrees C. There's no happy medium here, which is why I consider Ram Cichlids as NON COMMUNITY fish, despite widely being sold as such (and why so many of them die after a few weeks from Hexamita and other opportunistic diseases).> The Oto's settled in nicely and cleaned a 5 in piece of slate in a day. My question is about what to feed them when the algae runs low. You mentioned lettuce and peas, but is boiled cucumber fine? <Cucumber is NOT fine... it's mostly water. (To quote the immortal Samuel Johnson, a "cucumber should be well sliced, and dressed with pepper and vinegar, and then thrown out".> The Oto's are eating it right now and I was just wondering if it was healthy/ nutritious enough. <Your best bet is standard issue algae wafers, of the type sold for Plecs. These should make an adequate staple. I'm also a fan of offering Sushi Nori to herbivorous fish. You can buy this stuff from Asian supermarkets very inexpensively (here in England, it's under £1 for 10 sheets). Attach strips of the stuff to a lettuce clip and let your catfish graze. These two foods could be alternated through the week and should keep your Otocinclus in tip-top condition.> Thanks again. <Cheers, Neale.>

Re: Otocinclus; diet  7/29/08 I do believe that my water is not really too warm as it is a 5 gallon heater set at max. <It's not a question of belief. If the water is above 25C/77F, the Otocinclus *will* be heat stressed, and long term won't thrive and likely die prematurely. If the water is below 28C/82F the Mikrogeophagus ramirezi will be too cold. Their immune system will be weakened, and sooner or later they will contract an opportunistic infection and die. These two species live in completely different habitats. The Mikrogeophagus ramirezi inhabit thickly vegetated, sun-baked pools, whereas Otocinclus inhabit sandy or muddy fast-flowing streams.> And I will be moving 2 rams to the other side of the divider as all the eggs were lost to fungus/ infertilization (tear). <High temperature (28-30C) is essential for successful Mikrogeophagus ramirezi reproduction, as is very soft (<5 degrees dH), very acidic (pH 5-6) water. Outside of these environmental conditions, you will see precisely what happened here: infertile eggs, or even if the eggs by some miracle do get fertilised, the parents fail to brood them properly or the fry cannot hatch out. In any case, unless you picked up your fish wild caught or from a specialist breeder, don't get your hopes up too high. The quality of the "mass produced" Ram Cichlids is appallingly low. Fertility is low, and much of the colour you see is artificially induced using hormones and additives to their food. They also seem to be tanked up on antibiotics, and quickly weaken once they leave the fish farm. I hate to be a downer about these beautiful fish, but I simply don't recommend people keep them anymore. Much better is Mikrogeophagus altispinosa, a much easier to keep species sold as the Bolivian Ram.> I will also make sure I pick the wafers up tomorrow at work. Thanks <Cheers, Neale.>

You Say Po-toh-to, I Say Po-t-otto Do Otocinclus cats eat dark green Cyanobacteria in a FW tank? <Possibly, but are you sure you're dealing with Cyano?  It most certainly does happen in FW tanks, but plain ol' green algae is a likelier bet - and the Otos would most definitely chow down on that.  The best way to fight Cyano in a freshwater tank is to get some vascular plants to out-compete it; basically, the plants are more efficient, so they suck up nutrients before the algae can, so the algae misses out and dies off.  Myriophyllum, Anacharis/elodea, hornwort, or even a couple floating water lettuce would certainly help you in this battle.> Also what is the proper pronunciation of Otocinclus?  Like Otto-sin-klus or oh-to-sin-klus? <planetcatfish.com says "auto SINK luss".> Thanks! <Sure thing!  -Sabrina>

Otocinclus Meals Robert, <Hi, EJ, Sabrina here tonight, instead> I read your article on Otocinclus on wetwebmedia.com. Thanks. <Glad you enjoyed it!  I'm sure Bob appreciates the thank you greatly.> A couple questions:  In your article, you mentioned that they need wood to survive.  What kinds of North American woods are acceptable for Otocinclus?   <Pretty much anything that's been *very* well cleaned and either sinks on its own or is weighted will do.  Check out your LFS for driftwood ideas.> What state should the wood be in?  Fresh, weathered, decomposing, etc.?   <Very well weathered - as in, no bark remaining whatsoever.  Wood that is decomposing poses a problem as it will decay in the tank and make a genuine mess of things.> What is a good brand of sinking pellets to feed them?   <Frankly, my personal favorite dry food brand is Hikari, but I rarely (if ever) use algae wafers to feed my algae munchin' dudes.  Algae based frozen foods (Ocean Nutrition's Formula Two, for one example) are a good prepared food item to offer.> Will they feed on other vegetables besides the spinach, Nori, and peas you  mentioned? <Blanched cucumber and/or zucchini, perhaps the soft insides of green beans.... some years back, my Loricariids always appreciated the asparagus that I refused to eat as a kid....> Thank you very much. <You bet.  Wishing you well,  -Sabrina> EJ

Getting food to the Corys and the Oto   2/22/06 Hello WWM crew, I have searched your site and I think the single tiny wiggly white worm I just saw in my tank is Planaria.  It is a very very fine threadlike white worm of about 5mm length. I probably only saw it because I was sitting very close to the tank. Am I right in understanding these are from too much waste product and uneaten food? <Yes.> Do you have any delivery tips for the food?  I was afraid if I hid it the Oto and Corys would not find it either. I have a bit of driftwood with a plant on it that I can put food under but it seems nearly all the fish can wiggle in there to get it! I thought my tank was very very clean.  I change 25-30% of the water once a week with another bucketful or two changed halfway through the week as I don't like to see the Corys searching around for food in droppings. Yuk. I vacuum the open area of gravel once a week and stir up the other areas with the siphon hose as the vacuum wont fit amongst the plants.  I have quite a lot of live plants. My problem I guess is I have been overfeeding although everything gets eaten quickly. <I agree.  Your vacuuming technique sound very thorough.> I am always worried about getting enough to the Corys and the Otocinclus.  The other fish are total pigs and tend to eat everything. I feed a couple of pinches of flakes <Try backing off a bit.  Try to lure those speedy Tetras away by sprinkling a bit on one side of the tank, and then sprinkling the rest far away from them.> , two sinking Cory-food pellets <Feed just one pellet.  Break it up into a couple pieces, always drop it in the same place in the tank every day, so the Corys get into a pattern/know where to find it.  Feed the Corys about 1/2 an hour after you turn off the light tank light.>   and a half of an algae wafer once a day with a day of no food now and then. <Leave the wafer as a treat for every now and then.> Also feed a frozen bloodworm cube once a week and some cucumber every few days (the Oto loves that). <OK as long as you are subbing this for the other foods you described.> I have a 26 gallon freshwater tropical tank (AquaOne 620) with a filter and lights built into the hood Temperature about 78 degrees. Ammonia and Nitrites are zero. Tank has been set up for 10 weeks and is fully cycled. The tank is stocked with: I angelfish 3 black skirt tetras 5 Corydoras 2 dwarf Gouramis 1 Otocinclus <A bit heavily stocked for that size.  Probably contributing to the waste/food levels for Planaria and algae.  Your Angel will get quite large, produce even more waste.> I tried leaving the lights on a bit longer to grow some algae for the Oto...but instead of the brown algae I once had green algae has grown on some of the Anubias and Oto doesn't seem to make much difference. So that might have been a mistake? Do you think if I revert to my original 8 hours of light the Oto will eventually eat it all? <Go back to 8 hours.> Or maybe should I get an additional Oto? <Otos do prefer the company of their own kind, but you are already heavily stocked.> So much to learn.  Any advice you can give would be very much appreciated. Many thanks, Gillian  : ) <Jason N.> PS I think your site is terrific, you folk obviously love what you do although I expect if you get many more "My Betta sits at the bottom of his bowl" questions you might implode. <Thank you!>

Re: Getting food to the Corys and the Oto   2/22/06 Thank you Jason for your speedy response, I was very disappointed when I did my own sums and realized "no more fish for me"....well, in this tank anyway.  Everyone laughs when I talk about my next tank. <You've been bitten by the bug.  God have mercy on your pocketbook.> This one is a practice to see if I can keep up the enthusiasm before going mental on a giant tank. <I find that my largest tanks are the easiest to care for.  It is far harder to make most mistakes in 50+ gallons of water.> You know what?  I think I can! <Glad to hear it!  Now there is only the problem of what you're going to do with your current tank when you get a new one...> Thanks again from Australia, Gillian  : ) <Jason N.>  

Question for Neale about TFH article, 10 gal. stkg.  Otos f'    01/13/2008 Neale, <Hello Evan,> I read your article in the TFH about 10 Gallon stocking. I was wondering if you had a reason for not mentioning Otocinclus along with the Corydoras. Is there a specific reason to not add the Otos to a 10G tank or were you just limiting yourself to keep the article concise? <Yes, there was a specific reason for leaving them off: Otocinclus spp. have an abysmal track record in aquaria generally, the VAST majority dying within a few months of introduction. I would never recommend them to anyone without several years of experience, and even then, only when placed in a mature tank (lots of green algae/aufwuchs) and excellent filtration. This pretty much rules out the average 10 gallon tank received as Christmas present, which was the focus of the article. If you want an algae-eater, get cherry shrimps; if you want a catfish, get Corydoras hastatus or some other Dwarf Corydoras. Both these will prosper without anything more than an "average" level of care, i.e., water changes, proper food, etc.> I ask because I have a 10G with 9 Glowlight Tetras to which I would like to add 3 or 4 Otos (as soon as LFS orders some). <Think very carefully about this, and only if you have LOTS of green algae. Otocinclus really don't eat anything much besides green algae and the microorganisms therein. Brown algae, blue-green algae, etc. aren't substitutes! To get green algae growing, you'll need 2 Watts of light per gallon, at least. There needs to be a "turf" of green fuzzy algae on the plants and rocks. THAT'S what these little catfish eat. On top of that, you need plenty of water flow (at least 4x the volume of the tank in turnover per hour, and ideally 6+) and above-average oxygenation. Nitrates need to be close to zero, and certainly less than 20 mg/l. If you can't answer all these demands, then skip Otocinclus.> I perform 40% WC every 5 days, so I think I would be able to keep that many fish and maintain good water quality. What are your thoughts? <Best avoided, frankly.> Thank you, Evan <Cheers, Neale.>

Re: Question for Neale about TFH article plus Corydoras  1/14/08 Dr. Neale, <Evan,> Thank you for your responses to my questions about Otocinclus. Through my web-based research I thought that supplementing the Otos' diet with Nori and vegetables would be adequate, so I'm very grateful for your input on the matter. <You may be fine doing precisely that, but the cold, hard reality of the matter is that whatever people do, most Otocinclus don't seem to survive long in anything other than a big, mature tank with plenty of algae. Their diet is a subject of some discussion among hobbyists. They may be partly parasitic as well as algae-eaters: in aquaria they have been reported MANY times to eat the mucous and skin from large, slow fish. I have seen this myself, my Otocinclus causing a significant amount of damage to the body of an Awaous goby. Do they eat mucous only when hungry? Is it something they do regardless? No-one really knows.> On the subject of the Corydoras hastatus & C. pygmaeus: I currently have medium to large "aquarium gravel" (colored pebbles) up to about 1cm in diameter. Would this substrate be acceptable for keeping either of the above Corydoras species? <Acceptable yes, ideal no. With all Corydoras, the best results come with lime-free sand, simply because it's more fun to watch them plough through the stuff. That said, the midwater Corydoras species like Corydoras hastatus likely don't care either way.> If not, what kind of substrate do you recommend? <The best for a small, planted tank is unquestionably black sand. Looks lovely, and because it removes upwelling light, fish adopt their brightest colouration.> If I need to replace the gravel, what is the best method? <If you have an undergravel filter in your tank, best not to change the gravel at all. But if the gravel is purely decorative, there's no real problems. Just take all the fish out, put them in a tub or bucket with the filter connected to that vessel so the bacteria stay happy. Then empty out the aquarium, remove some or all of the gravel, and then add the cleaned sand to a depth adequate for the plants. If no plants (or at least no plants with roots, as opposed to epiphytes) then you only need 2 cm/1 inch of sand.> Again, thank you for your help. Evan <Happy to help, Neale.>

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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