# Otos - 30L Suitable??



## Richard Dowling (20 Nov 2011)

Hi All,

I am choosing some new fish for my 30L fluval ebi, Its got a fairly large piece of bogwood in it, java ferns and a little vallis and Alternanthera reineckii (which isnt doing too well under low light)

Ideally Id love to have some Harlequins and Otos, both fish have really caught my eye. Im pretty sure Harlequins are not suitable for a tank this small but have heard that Otos are?? Can anyone comment on both of those? I have dug out August 2010's PFK Mag and tried to find out what Otos are suited to but there doesnt appear to be a mention of minimum requirements. It does say they need to be in groups of 6, Im unsure whether 6 is too many in this tank. I beleive I have read in the past that Harlequins need more than 30L.

I may go with Glowlights instead of Harlequins if I cannot have them.

Thanks in advance


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## dw1305 (20 Nov 2011)

Hi all,


> but have heard that Otos are?? Can anyone comment on both of those? I have dug out August 2010's PFK Mag and tried to find out what Otos are suited to but there doesnt appear to be a mention of minimum requirements. It does say they need to be in groups of 6, Im unsure whether 6 is too many in this tank.


There are 2 major problems with _Otocinclus_, although in some ways they are 2 different facets of the same problem. 

The first is that they don't travel very well, so you need to buy them from a shop where the staff understand that they need special feeding, and that they become easily stressed. If you can find a shop where they are cared for, that is half the battle, I think they also needed a planted tank for long term maintenance, something that a lot of LFS don't provide. They need weaning onto some un-natural food fairly quickly, as they only eat a limited range of algae and once they are starved they are unlikely to recover. I've found a method for weaning them onto cucumber that works fairly well, once they are eating cucumber you can introduce more nutritious vegetables and algal wafers etc. 

The second point is that they are very un-forgiving of poor water conditions, and become easily stressed. For this reason I wouldn't suggest them for a small volume tank, as stability is much  more difficult to maintain in small tanks.

If you think you can maintain high O2 readings and good water quality in a small tank, I don't see any reason for why you can't keep 6, and my suggested tank mates would be a small shoal of  _Corydoras pygmaeus_.

cheers Darrel


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## greenjar (21 Nov 2011)

Hi Dowheim.

Darell really knows his stuff, so that is some sound advice there



			
				dw1305 said:
			
		

> I've found a method for weaning them onto cucumber that works fairly well, once they are eating cucumber you can introduce more nutritious vegetables and algal wafers etc.



This would be interesting and helpful for many folk I bet, if you wish to share - would be great, may help reduce the lengh of time experimenting and holding thumbs    

Thanks guys


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## foxfish (21 Nov 2011)

Good post Darrel, I have never even seen them for sale where I live but I have always fancied owning some.
It no fun buying fish & watching them die!


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## idris (21 Nov 2011)

A related question:
I have / had 6 Otos. But in the last few months I've rarely seen more than 3 at a time. They have plenty of places to hide wih no chance of me seeing them, but I've had a spate of fish deaths recently, so I don't if I've lost any.

Is blanced cucumber a good way of gettting them to break cover? Or is there something gauranteed to tempt them (other than diatoms) without having to compete heavily with other fish?


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## spyder (21 Nov 2011)

Got 4 otos in with 6 Cpds in a 28l aquastart 320. Well planted and slightly overgrown. No deaths or water quality issues. If you add them make sure the tank is fairly well established.


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## dw1305 (21 Nov 2011)

Hi all,


> This would be interesting and helpful for many folk I bet, if you wish to share - would be great, may help reduce the lengh of time experimenting and holding thumbs


 Method is probably putting it a bit strong, but I noticed that Otos like resting on upright twigs that were just wider than their bodies, and that they tended to rest in areas with some current. 

My tanks all have braces, so I cut a series of bamboo canes that I could wedge in vertically under the bracing and then I used an elastic band (I use the blue ones that come on bunched spring onions or water-cress) to fasten a round of cucumber to the cane, about 1/3 of the way up from the substrate. I start with 3 or 4 canes/cucumber and even if the Otos don't initially show any interest in the cucumber, I change it for a new bit every 48 hours (so that it is fairly slimy, but not totally disintegrated). 

As soon as the Otos are visiting the cucumber (probably mainly initially at night), I add a piece of green bean or pepper to the cucumber or swap it for courgette etc. Once other vegetables are being sampled I stud the cucumber/courgette with pelleted food, or add the occasional prawn etc to the veg.

I always keep some vegetable for the Otos in the tank and I always make sure there is a cane in the feeding spot, if I need to change their feeding position I put another cane in with cucumber where I want them to feed, once they are using this one, I take the first cane away.

This is a photo from a few years ago showing the canes (and a male _Apistogramma_ "Steel-blue").






cheers Darrel


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## idris (21 Nov 2011)

dw1305 said:
			
		

> ... I noticed that Otos like resting on upright twigs that were just wider than their bodies, and that they tended to rest in areas with some current ...


Makes sense. When I do see mine during the day, they're almost always sitting on my Valis near the intake.


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## Richard Dowling (22 Nov 2011)

Thanks Guys,

As you mention their need for good water quality, it brings me to my next question, which may be a dum one. I have read that Oto's dont like Nitrates at all. I dose nitrates as part of my EI (at the moment quite high levels to try and kill my BGA bloom) can Oto's still survive with dosed levels of Nitrate? I do 50% water changes weekly.

Also, regarding the Harlequins.....are they 30L suitable or is it definitely a no no?


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## YzemaN (22 Nov 2011)

30L might be a bit small as Harlequins are very active swimmers. I would hesitate to put them in anything smaller than 3ft, but I've seen them in 2ft aquaria, though.

Sent from my Android using Tapatalk


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## spyder (22 Nov 2011)

No comment on harlequins.

As for Nitrates and Oto's. I dose EI in all tanks and have no issues. Oto's are know to be very sensitive to ammonia though.


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