# the correct numbers for the tank



## Fred13

Hello,

As i am getting closer and closer to start up my tank i am considering which are the best numbers about the fauna i am thinking to get.

Tanks size 65 gallon , 100 x 50 x 50.

I am thinking for a school of ember , something like 20 of them.
Otocinclus
panda cories
amano-rcs

How many otocinclus you believe i should get in order to achieve better behaviors and less shyness?
As for panda i guess a group of 6-8 would be nice for them /

Thank you


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## tam

Has anyone noticed a difference in the shyness of Otos in relation to species? It seems like the stripe, gap, tail spot ones I have are more out going than the solid stripe, but I don't have a big sample size.


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## Fred13

I personally dont know but i guess numbers are the key for all of them..


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## Fiske

For both cories and otos; the more the merrier. Both species are found in flocks of 100-1000s in the wild.


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## Fred13

Fiske said:


> For both cories and otos; the more the merrier. Both species are found in flocks of 100-1000s in the wild.


At 65 gallon what do you suggest? 8 and 8 ?


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## castle

12 otos minimum as I’ve lost for 30/40% of my Otos within a day of introducing them. Also if your tank is containing wood etc then 12 otos will be pretty much unnoticeable.


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## BubblingUnder

I would have thought that more is better in a mature heavily planted tank. Sheer numbers should mean they interact as a shoal & you see them more. I only have one Otto in a 125L tank I don't see him very often when I do he seems healthy but seems to prefer to eat algae off the wood/plants rather than the glass.


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## Edvet

If you have the possibility of "algeing up"a few stones ( in a shallow tank, lots a of lights and ferts) you can introduce them in the tank with new Oto's ( or in the quarantine). Most of them havn't eaten in a while when you get them.


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## tam

I've 7 embers, 6 otos and waiting on 8 cory hasbrosus in 15 gallons. The Otos are very active at meal times and early mornings, but can vanish completely too. 20-8-8 would be quite lightly stocked for a 65 gallon. I'd double the oto/cory numbers, but I guess it depends which fish you want to be the noticeable ones. One day I'd quite like a big tank with a giant shoal of Otos, so I'm a bit biased.


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## mort

It's a complicated answer because it depends on a few factors. The size of the tank would allow decent sized groups of each species but it depends on how busy you want the tank to look like and what type of scape you are planning.
20 embers would be a good start in a metre long tank but you'd be surprised how sparse they will look. The same could be said for the other species unless you have large groups.

The best advice I could give is to add fish in small groups and then up their numbers if you think they need it later. I wouldn't be surprised if a group of 40 or so embers would be needed to look good in such a long tank but it does depend on your filtration and what you are trying to achieve. For fish behaviour I think a dozen of each would be the minimum I'd consider and it's really only the pandas that will grow, so you should be able to see what looks right pretty quickly.


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## zozo

Oto's seem as described to be a hierarchical schooling fish with quite a induvidial personality. I guess kinda personality is what you need to develop a sense of status in a community. They also seem to be very stress thus kinda emotinaly sensitive which likely stands in relation to this specific characteristic.

I have no idea if this is a typical male and or female behavior and since as far as i know it is realy difficult or maybe even impossible for a simple hobbyist to determine sex and buy them accordingly. than we can only assume maybe both sexes live by the same rules. than it's only obvious that only a rather large number has the best chances to develop healthy equaly balanced hierarchy in the group.

How much is the million dollar qeustion nobody probably realy can't answer.. 10? 20? 30? even more. If you believe the general consensus written in regular databases it's 10 +.. I personaly guess bigger is better..


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## Fred13

Your answers were very clear to me and thank you. I kept otos at the past and i still remember that i was glad that i never lost any. Maybe luck? Maybe the lfs i took them had them in a good shape..
I believe i will go by starting with some smaller groups and then add wherever is needed. 
My filtration will be pretty powerful but i will go slowly to give time for the bacteria in filter to get stronger.
I will go for 20-8-8 and shrimps . I believe my filter will handle these numbers pretty well at the beggining.
Then i will go for more!
I ll keep you updated! Thank you so much!


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## Chubbs

Ottos are great I have 12 in my 240ltr tank and barely see them. They’re beat in an eatabliahed tank as they seem to eat algae and biofilm and have ignored all my attempts at feeding them algae eaters, cucumber and courgette. They also appear to love shade, often sitting on the underside of leaves at the shadier end of my tank and are most active during night.

This has just been my experience with mine.


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## sciencefiction

I had 4 ottos that lived for some good years in a 100G tank. Mine too weren't keen on veggies and I was afraid to add more ottos to that tank in case they ran out of natural food. It wasn't as if I had much visible type of algae suitable as otocinclus food. But they were quite active and definitely not shy at all. You'd notice that in bigger tanks ottos are way livelier. Mine were active and playful, swimming in and out of flow, from side to side of the tank like rockets, doing circles on the glass, etc..They were constantly on the go. At some time I kept a single zebra otto in another planted 100G. I could see it 99% of the time I looked in the tank. It kept going around like a butterfly. Having said that, ottos do like each other's company and would follow one another from time to time, as well as "sit" around together on a branch of wood or a big plant.

I like your choice of stock and I think ottos would be ideal in such a set up, as long as it is cycled and established.


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## John White

Before you buy any Oto's read this https://www.myaquariumclub.com/before-you-buy-otos-please-read-this-8507.html


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## dw1305

Hi all, 





John White said:


> Oto's read this https://www.myaquariumclub.com/before-you-buy-otos-please-read-this-8507.html


That is a good article.

cheers Darrel


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## alto

Agree but somewhat confused about the use of cyanide - videos I've seen of otocinclus harvesting, show vast numbers of crazy squiggling fish in the net or basket

One lfs brings in Oto's from Brazil or Columbia, these often arrive small - tiny in size, but active & feeding & shop experiences significantly fewer losses


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## Tim Harrison

To quote from the article...

"For one thing, their diet is less typical than many common fish we keep. German fish keepers refer to Otos as ‘Aufwuchs’ eaters. This is a term they use that means a fish is more or less an *obligate* algae grazer...Some Otos don’t learn to eat anything other than fresh algae, so feeding them algae tabs/pellets or even fresh veggies, won’t be a guarantee they eat well."

Hallelujah ...I feel somewhat vindicated; this fits in exactly with my own observations. I took a fair amount of flack a while back for my skinny otos...this was after I tried my damnedest to wean the little blighters off algae and on to every conceivable poached vegetable from our own shores, and from the foreign foods isle, and much more besides...this and that brand of algae wafers etc 

Try as I might I've never got them to eat anything that wasn't algae. Which is always a problem since there is never really very much algae in my tanks 

So, I have learnt from experience that as much as I'd like to keep them in the numbers they've become accustom to in their natural environment it's simply unsustainable in an aquarium 

I have two in my current shallow scape and they have fairly well rounded bellies so I guess I've got the balance right, and they seem very happy in each others company


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## AverageWhiteBloke

I've been finding my ottos appear to be livelier without co2, same for my corys. Also could be oxygen related as the tank they're in now is air driven. I can't honestly say they shoal though as such. They will all hang about in the same area but if a couple wander off and do their own thing they all don't follow. Numbers don't seem to make much of a difference either. I've had 4/5 in and maybe see a group of 3 together the rest out and about, at one point I've had maybe 9/10 and still they seem to stay in a small group of 4. Could be that the small group hang about where I tend to put food, the ones who are out for a wander tend to go back to where the group usually sit and another one will wander off.

Food wise, they seem to spend the majority of their time rasping at decaying leaf litter that's been in for a while, love cucumber, in fact when cucumber is in maybe once a week some just won't move from it all and just balloon. They will push each other out the way when feeding on it. They also particularly like stripping down roots off floating plants and if you have an area of dense floaters there's something in there they like. I suspect that its a bit of a soup of bacteria and decomposing plant matter. Often see mine upside down skimming the surface with their noses poking out the water. Sometime I even poke my finger in there in case they are dead but they always swim off.

As for algae wafers, I did get some small hikari ones but my amanos just snatch them and disappear now they are a good size. When I put big algae wafers in they attract too much attention, every fish in there as having a go at them and the ottos tend to get pushed out, especially by the corys but they do have a go at them. I tend to put them in about 15 mins before lights out so they ottos know they are there in the hope the other fish leave them to it and go to sleep. All I know is in the morning the wafer has gone, who ate is anybody's guess.

That's just my observations after keeping them for a number of years. The small ones in the pic below have only been in the tank one day and took to cucumber straight away. There's also a new one at the bottom feeding of an oak leaf which has been in the tank abut a week. The larger ones I've had for over a year I would say.


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## sciencefiction

Tim Harrison said:


> I feel somewhat vindicated; this fits in exactly with my own observations. I took a fair amount of flack a while back for my skinny otos...this was after I tried my damnedest to wean the little blighters off algae and on to every conceivable poached vegetable from our own shores, and from the foreign foods isle, and much more besides...this and that brand of algae wafers etc



Besides one otto which I raised from accidental spawning and ate zucchini, the shop bought ones didn't really eat anything else but what was on the glass and plants, hence I never kept a large group although I always wanted. I think that as long as they're in a big tank that provides large surface area for food, and one has a few only, they'd be fine but mine did not last when I moved them to a small tank although I had them for 4 years in a 100G previously. As far as I know, they need access to food 24/7 so even if they get to fish food/veggies, its not enough. And algae never grows when you want it.


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## alto

I can never get my Otos to eat anything vegetable  
but when I feed frozen bloodworm  it's like an Oto feeding frenzy 
(I guess mine forgot to read the book )


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## Tim Harrison

I've often wondered about that @alto ...they're such a diverse group it's difficult to know which species you've bought and what their exact feeding habits are. I guess we could potentially rewrite the book if we knew for sure.


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## castle

I have had a bit of push back in the past online with my thoughts on otos, but I still stand by it. 

In short, if you're buying otos, buy double the amount you planned on. They die heavily, well that's not always true, but you should expect some not to make it. Otos species get mis-sold all the time, you probably do not have O.Affinis.
Even when buying really healthy looking fish, some will drop off. I think most of the damage is done in collection/transit.

Otos will come round to eating vegetables, but to encourage it house them with other algae eaters, Farlowella work really well here. Otherwise your weaker plants might get damaged. 
They're very hardy, once the weak have died. I find them to look more comfortable at 22° than 25°. 

I have 7 otos in one of my tanks, it's a jungle I admit. I bought 12 for that tank, sadly. They did spawn, but nothing came of it. Maybe I'll put a bit more effort into them later this year. 

Also, good article.


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## castle

tam said:


> Has anyone noticed a difference in the shyness of Otos in relation to species? It seems like the stripe, gap, tail spot ones I have are more out going than the solid stripe, but I don't have a big sample size.



Yep, vittatus (probably) is far more nervous than macrospilus in my experience. Much smaller too.


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## alto

Tim Harrison said:


> what their exact feeding habits are.


I forgot to say, my Otos do love any sword plants I might care to provide, and the Nymphoides hydrophylla 'Taiwan' will be allowed to flourish, until, suddenly it becomes the #1 Favoured Dish


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## tam

I've been trying Rapashy solent green on mine, it's meant to be specifically tailored to aufwuchs eaters. They like it, although I don't think I've quite mastered the right cooking technique as mine doesn't gel very well.


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## AverageWhiteBloke

I watched this on youtube and will get round to making some one day. I use a bbq skewer to put my cucumber on and for some reason the ottos love rasping up and down it even when the cucumber has gone so maybe worth a try.


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## dw1305

Hi all, 





AverageWhiteBloke said:


> I use a bbq skewer to put my cucumber on and for some reason the ottos love rasping up and down it even when the cucumber has gone so maybe worth a try


A bit of bamboo cane for me. I'm pretty sure it helps with getting them acclimitised to vegetable food, because they really like resting on a vertical bamboo cane (it is about the same width as their body?) even when it doesn't have any food on it. 

cheers Darrel


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## sciencefiction

Tim Harrison said:


> I've often wondered about that @alto ...they're such a diverse group it's difficult to know which species you've bought and what their exact feeding habits are. I guess we could potentially rewrite the book if we knew for sure.



Well ottos are not strictly algae eaters exactly. They eat the micro-organisms developing in Periphyton/Aufwuchs, which is partly algae, partly some other micro-organisms living within,  so I am not surprised them eating bloodworms. If one tends to be obsessive about clean glass, and has fast growing plants that have no time establishing biofilm, ottos may starve.... Mine did not touch fish food. I got excited a few times but thinking of it now they just used to sniff it and swim away. Even the otto I raised never ate fish food and refused veg after a while. 

I have hillstream loaches, and although they're supposed to love aufwuchs and algae, etc...and are stuck to the glass most of the time, they go bananas for fish food, they make a sandstorm while eating  I've never seen that happen with ottos.


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## AverageWhiteBloke

Yeah I would agree with that, when I watch mine they pay little attention to commercial food. They spend most of their time on anything that's decomposing matter so I would suggest its the bacteria on decomposing matter they are after. They appear to hang on the glass walls but more resting than grazing and the glass gets clean pretty quick. They seem to graze more on decomposing plant litter, the sponges on the filter and wood. Same as the floating plants where there's dead leaves and still water which turns into mush. This "mush" appears to be the favourite. I could quite easily imagine that's what's going on with the cucumber as well. When it first goes in they will sit on it and have a rasp but after it decomposes a bit and turns mushy that's when they really get tucked in. I would say their main diet is the micro-organisms and bacteria breaking down matter than the actual matter itself. 

Maybe that's why people struggle with them in scrupulously clean show tanks, what they need is some rubbish to sift through. Like I previously mentioned as well I don't think they are fans of co2 injected tanks either, it seems to have a debilitating affect on them where they sit not doing much most of the time. My ottos and sterbai came from a co2 injected tank and although healthy enough there wasn't much to see, in my non co2 tank with oxygenation via an air driven sponge filter they are very active, same goes for the sterbai, they would just sort of sift around the bottom but in this tank they shoal as a group from side to side along the front which I never saw in the other tank.

I would say best way to keep them would be in well oxygenated non co2 tank with plenty of decomposing plant matter to sift through which is why I set up This Project. Seems to have worked and I haven't experienced the losses of biblical proportions normally associated with these fish. Only lost one so far even with some new fish in poor health when bought but they rest seem to have got on their feet very quickly in this kind of set up.


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## sciencefiction

AverageWhiteBloke said:


> I would say best way to keep them would be in well oxygenated non co2 tank with plenty of decomposing plant matter to sift through which is why I set up This Project. Seems to have worked and I haven't experienced the losses of biblical proportions normally associated with these fish.



I never noticed them eating decomposing matter but 4 of mine lived in a sparsely planted community tank for over 4 years. They were strictly "glass cleaners" from what I noticed. I never cleaned the glass of that tank. The losses are not immediate except for the odd poorly otto that comes emaciated. I haven't had a problem keeping them alive after purchase. I've lost just one otto to emaciation and one getting stuck behind the internal filter. But they can disappear one by one over the course of a year if not kept in a suitable environment, whatever that is. That's how I lost my old ottos as they had to move to a small tank when the big one broke(from a 100G to a 10G tank)

 I also raised a baby otto in a bare tank with just sand and algae/biofilm on the glass which tank had been running for some years prior and the baby found itself there as an egg via some plant cuttings( I had just removed all plants and shrimp from the tank to rescape when I noticed something small "fish" looking wise stuck to the glass ...All that after catching over 300 shrimp  So I kept the tank running and never rescaped...

  Then I moved it to another bare tank that had just a couple of anubias in. There was sand and oak leaves for the kuhli loaches and some manzanita branches.  I lost it along with its father when that tank broke, sadly never found it on the floor although I recovered one,  but it was happy until then for a good while. So in my view, a planted tank isn't even needed for ottos....They need an established tank with access to biofilm of some sort, small number of grazers to limit competition(I had 3 in a 30G tank), and perhaps you're right about decomposing matter, although I never noticed my ottos paying much attention to oak leaves...


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## John White

I origonally bought 5 Otos, lost a couple then bought 6 more from a different lfs with the same results ending up with 3 which fingers crossed seem to be doing fine. I have witnessed a couple of them dying, they seem to have rapid jerky movements like a heart attatck then finally just die...............not pleasant viewing at all. I did wonder if it was something I was doing wrong but as all the others in the same tank seem happy and none have died I looked on line for clues, hence the link I posted earlier in this thread. The three I have left get a piece of blanched Courgette or lettuce leaf depending what we have in the house at the time and they love it. The Courgette soon looses all it green skin as they happily much away at it. I feed algae wafers which my salt and pepper Corrys and Amano shrimp love but the Oto's totally ignore.
I think the thing with Oto's is make sure they have plenty to eat then you have done the best you can and just hope they are not to damaged internally from their capture.


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## AverageWhiteBloke

I wonder, as these fish seem to graze pretty much non stop with only small stomachs and limited nutritional value to the stuff they eat whether it doesn't take very long without access to food for them to take a turn for the worst. They've been in transport for some time no doubt starving and nothing for them in the LFS for however long they are on display. Maybe their stomachs have shrunk and then they get into a situation where there's plenty of food and fill their boots causing pressure on the swim bladder? The death throws when these things go seems to be inability to maintain balance in the water. Just thinking out loud.


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## sciencefiction

AverageWhiteBloke said:


> Maybe their stomachs have shrunk



I read once that if they're not fed for a period of time, their gut fauna is altered and the reason for emaciation is lack of correct gut bacteria. That article mentioned that for that reason ottos should be kept in groups because they can "exchange" gut bacteria???.....not sure how true that is...


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## Looneeyy

Wondering about the up keep of ottos? never kept them but heard there very difficult? Sorry to add to the post!


Sent from my iPhone using Tapatalk


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## tam

If you get them successfully through the first few weeks they seem pretty tough. It's just that initial period which is the problem.


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