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Otocinclus troubles

Joined
7 Jan 2021
Messages
146
Location
Nottingham, England
Hi everyone,

I've got 4 tanks with probably about 50 otocinclus macrospilus between them. After lots of trial and error my survival rate is really good - about 90%~ after two months (though not gotten them to breed yet!) - but lately something seems to be spreading in my main tank and I'm not sure what it is.

When I come to do the weekly change I always find there is one that has bloated up really large (below). The affected otocinclus always dies within two days of being spotted, and floats to the top rather than the usual sinking to the bottom. It's gotten to the point that I am euthanising them as soon as I spot them to try and stop it spreading.

I took some samples from inside the belly of the latest one I euthanised. Only consistent finding is these egg-like things under microscopy, but I'm not entirely sure whether they are just bubbles to be honest.

IMG_20211205_164222.jpg
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Any ideas?

Cheers
 
A couple of questions; how big are those 'egg-like things' and where were they? In the stomach itself or in the body cavity generally, or?
And as @jaypeecee asks, what are you feeding them, - and has this changed recently?
 
Hi @spleenharvester

May I ask - what are you feeding to your Otos?

JPC

Generally don't supplement anything to any of the four tanks, there's a ton of biofilm.

A couple of questions; how big are those 'egg-like things' and where were they? In the stomach itself or in the body cavity generally, or?
And as @jaypeecee asks, what are you feeding them, - and has this changed recently?

Not visible to the naked eye - microscopy pictures were from a section of bowel. No changes to feeding.
 
Hi all,
Generally don't supplement anything to any of the four tanks, there's a ton of biofilm.
I'd probably supplement their feed with <"some leaves and vegetables">. They are quite selective grazers and may not be getting enough food. I use activity as a good measure of how well fed they are, if they spend a lot of the day <"resting on Echinodorus leaves etc">. they are probably fine. If they spend a lot of the day swimming around? it isn't a good sign.

cheers Darrel
 
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Hi @spleenharvester

Of course, the problem you are seeing may be nothing to do with feeding. But, I'll just add another two penn'orth from me. And, as @dw1305 has pointed out, Otocinclus do need vegetable matter in their diet. Soft algae seems to be important. Please take a look at the following video. Repashy Soilent Green is Repashy's way of simulating Aufwuchs...



JPC
 
Thanks for your responses everyone - I had a few more look like this and euthanised them immediately, since then I've had no cases, so I think it's safe to assume it was something infectious :)

As an aside, I have tried Repashy before, but couldn't get the damn thing to stick to rocks without disintegrating!
 
As an aside, I have tried Repashy before, but couldn't get the damn thing to stick to rocks without disintegrating!
Hi @spleenharvester

I have not tried sticking Soilent Green to rocks. In fact, I don't stick it to anything. I mix it up as quickly as possible - before it sets. Then, refrigerate it until it sets. When it has set, I remove it from the fridge about half an hour before it's needed. Then, cut thin slices off it as required and just drop it in the tank. It sinks immediately.

JPC
 
I did occasionally supplement seaweed sheets (Ocean Nutrition I think) on the recommendation of someone and the Otocinclus I had seemed to be quite keen on it... not as much as my Nannoptopoma sp.peru (name may have changed now this was a few years ago) they used to gobble the stuff up

Whether this was beneficial to them nutritionally is another matter
 
Thanks for your responses everyone - I had a few more look like this and euthanised them immediately, since then I've had no cases, so I think it's safe to assume it was something infectious :)

As an aside, I have tried Repashy before, but couldn't get the damn thing to stick to rocks without disintegrating!

How large are your tanks?

Even if they are very large tanks you will most definitely not have enough biofilm to support 50 Oto’s - likely not enough to even support 20 Oto’s.

As Darrel says, you need to be target feeding them like any other fish. Opinions will no doubt differ in frequency of feeding, but I would say a decent (half inch thick) slice of cucumber or courgette, and an algae wafer (such as the Hikari type), alternating every 2 days in every tank minimum.
 
but I would say a decent (half inch thick) slice of cucumber or courgette, and an algae wafer (such as the Hikari type),
I agree with you re the amount of biofilm and courgette would always go down well but I've kept a lot of otos over the years and not one has ever expressed any interest in algae wafers (hikari included)

Did yours go for them?
 
I agree with you re the amount of biofilm and courgette would always go down well but I've kept a lot of otos over the years and not one has ever expressed any interest in algae wafers (hikari included)

Did yours go for them?

Yeah, every one I’ve had has chowed down on them, but I have read other folks report a lack of interest in them also.

The biggest problem I have is giving the Oto’s chance to get to them before the snails swarm it.

If your Oto’s are eating the courgette, you can always try and press a full or part algae wafer into it before serving, so they get used to the taste. Once they get used to recognising the smell it might wean them onto it.

My Oto’s might be bit unusual though - they like to hang out with the Cory’s and I’ve regularly seen them shoaled up together on the substrate actively eating sunk fish food, brine shrimp or grindal worms with the Cories.
 
My Oto’s might be bit unusual though - they like to hang out with the Cory’s and I’ve regularly seen them shoaled up together on the substrate actively eating sunk fish food, brine shrimp or grindal worms with the Cories

Yeah I've experienced the same before and it did make me laugh

No doubt I will keep otos again at some stage and I will be a bit more creative with getting them to acknowledge algae wafers but it's a mystery to me the mixed reports of some going for them and others, like the ones I've kept, having no interest whatsoever
 
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