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Are Otos more sensitive to Co2 than other fish?

Sacha

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Hi all,

I have had a lot of trouble keeping otocinclus alive in my high-tech planted tank. There is plenty for them to eat, and I cannot see of any particular reason why they always seem to get sick and die.

The fish appear healthy in all other respects (they have full bellies, gills not particularly red).

Is it Co2 toxicity? My other fish (tetras, barbs, cory) don't seem bothered in the slightest by the Co2. But do the Otos have a lower tolerance for Co2 than these other fish?

Cheers.
 

karla

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I can not say if they are more susceptible than other species in general, but the ones I tried were definitely more delicate than other fishes and seem to take quite a long while to acclimatise.
 

zozo

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They are well known to stress easily and also die of it. They seem to be very hardy when it comes to water quality, but stress is the most commen cause for them to perish. Keep on watch, specialy at night, they maybe harassed by some barbs chasing them or maybe by some other fish.
 

Sacha

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Thanks for all the replies. I'll keep a close eye on them to make sure they're not being pestered by the other fish.
 

zozo

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I do not know what kind of barbs you're holding. I guess keep an eye on them, some barbs have the habbit to harass other fish.. Tiger barbs are the best example, they love to chase and nibble fins..
 

Sacha

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Pentazona, they are pretty placid. It could be the silvertip tetras causing aggro.
 

zozo

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An other thing with the oto's is, a heavily planted tank with co2 will also be heavily oxygenated. In a tank like that oto's will be very active during day and night. They are very playfull and will look like they never get tired playing all around the tank. If an oto is inactive for longer periods and hiding a lot, thats a sign for them being stressed or not feeling safe. Which you often see in poorly planted tanks like in some aquarium shops. Just laying on the bottom feeling unsafe not tracking attention.
 

dw1305

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Hi all,
But do the Otos have a lower tolerance for Co2 than these other fish?
I think they are quite sensitive to high CO2. A lot of Loricariids are. Apparently they will gulp air like a Corydoras, but I've never seen mine do this.
In a tank like that oto's will be very active during day and night. They are very playfull and will look like they never get tired playing all around the tank. If an oto is inactive for longer periods and hiding a lot, thats a sign for them being stressed or not feeling safe.
I've found that they become quite nocturnal as they get older, they only become active in the evenings and at night. One of mine is at least 4 years old, so they are potentially quite long lived for a small fish.

cheers Darrel
 

zozo

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Hi all, I think they are quite sensitive to high CO2. A lot of Loricariids are. Apparently they will gulp air like a Corydoras, but I've never seen mine do this. I've found that they become quite nocturnal as they get older, they only become active in the evenings and at night. One of mine is at least 4 years old, so they are potentially quite long lived for a small fish.

cheers Darrel

;) I dont want to nitpick, but 80 % of the pleco family branch are found in swift flowing clear well oxygenated streams. In invironments like that they thrive best. Actualy almost all available pleco's on the market need a special tank to meet these conditions and 90% of the owners don't, becuase the fish looks healthy and strong and can do in lesser conditions then optimum. All a fish can do is breath, eat and swim and if you see a change in that you're already welll to late with doing your home work.

I guess we're all doing our homework and if we keep fish with our plants we should have acceptable numbers when we talk high levels of co2 which also means high oxygen levels. If you combine this with a steady flow, your oto will feel like in heaven and shoot through your tank like little dart arrows with sucker cups.. Anyway, if the co2 is level excels the oxygen level that much so an oto will die of it then you don't have a fishtank but a torturechamber, where even a goldfish wouldn''t feel very well..
 

Sacha

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I have high Co2 levels, but massive steady flow and (I think) high oxygen levels. My ottos are all inactive day and night. It's rare that I see them move.
 

Julian

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As someone who has nuked their tank with CO2, my Ottos were actually the last to die. The SAE's and Galaxy Rasboras were the first to go.
 

zozo

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These are my oto's :) in the tank since yesterday morning, 7 of them helping the 7 shrimps. The rest is not home yet. In the shop they all where just still on the bottem not at almoving around. I brought them home and the feast began. Actualy i don't know them other than this in my tanks, i've bein without tank for a great deal of time, but oto's haven't changed. Always on the move playing and shooting around the tank day and night. Unfortunately not the best nor most beautiful vid at the wrong time of day, shot 25 minutes ago, just as a reference for you how oto's should act. When i put the camara away they come to the front of the tank, like they are pestering me. And this a fairly new tank, heavily planted, but not grown in yet.
 

dw1305

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Hi all,
I dont want to nitpick, but 80 % of the pleco family branch are found in swift flowing clear well oxygenated streams. In invironments like that they thrive best. Actualy almost all available pleco's on the market need a special tank to meet these conditions and 90% of the owners don't, becuase the fish looks healthy and strong and can do in lesser conditions then optimum.
I'd definitely agree with that. A lot of plecs are rheophilic, and people who keep them need to understand that they require specialist care.

Fish like Hypancistrus will still gulp air when they are oxygen stressed, although they have lost the specialized gut morphology that would allow them to extract any oxygen from it. The ability to extract atmospheric oxygen is thought to have been inherited from the common ancestor of the Loricariids and Callichthyidae, and is retained in <"Common Plecs etc. which are tolerant of low oxygen"> (I assume the fish was actually a <"Pterygoplichthys"> sp. plec ).

I got to know a couple of Bristol plec breeders and because of this I became aware that even really skilled fish keepers were losing large rheophilic plecs to low oxygen levels. I wrote an article that covers oxygenation specifically for Plec keepers - <"Aeration and dissolved oxygen.....">, it has had a few homes, but currently resides at <http://plecoplanet.com/?page_id=829>. I'm biased, but if I could only keep one article on fish keeping, and had to destroy all the others, I would keep this one.
As someone who has nuked their tank with CO2, my Ottos were actually the last to die. The SAE's and Galaxy Rasboras were the first to go.
I'd expect all these fish to be susceptible to low O2/ high CO2 (from <http://www.ukaps.org/forum/threads/co2-ph-level-in-planted-tank.26559/page-2>).
<"Fish Respiration">. As a general rule fish from cool, fast flowing, highly oxygenated water (Hill stream Loaches (Sewellia lineolata etc., some "L." numbers (Chaetostoma spp, Pseudolithoxus spp. etc., Salmonids) are most at risk from high CO2, and for the same species large fish are more at risk than small fish (due to the differences in the body volume (^3) to gill area (~^2) ratio).
cheers Darrel
 

zozo

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Hi all,Do you feed your Otocinclus vegetables?

cheers Darrel
Not yet :) but i will if they need.. For now there is plenty in the tank, that's why they are the first to arive after the shrimps. There are also a bunch of snails which came with the plants. And i see them grow daily at an exeptional rate. That means food in the tank. I never over feed my fish and even if you think you see nothing, but there is always food in a healthy tank, like in nature. Fish have a very slow metabolism and they are very easily over fed. Let them work for it, like we have too, i just keep a close eye on them and feed as scarcely as posible. They don't need to be fat and lazy. I have something like a little pond in the yard with a lot of elodea, i rather take a bit of choped elodea with some algea on it then cucumber or carrot all the time. elodea is very good food for most fish.
 

dw1305

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Hi all,
Not yet :) but i will if they need......Fish have a very slow metabolism and they are very easily over fed. Let them work for it, like we have too, i just keep a close eye on them and feed as scarcely as posible.
OK, they look fine and have settled in well, but it is a little different with Otocinclus, because they are specialized feeders on a relatively small range of aufwuchs, they basically graze all the the time when diatoms are present. If diatoms aren't present they search for a new source of food, they don't know they are in an aquarium, so they just continually swim around looking for "new" grazing surfaces. Unless you have a huge planted aquarium, and relatively low stocking, they will rapidly exhaust all the natural food sources, become starved and stressed and eventually just waste away. People often say that their Otocinclus dying wasn't a food issue, because they had "plenty of algae", but most algae isn't food for Otocinclus.

As well as plants and hard surfaces they will also <"graze leaf litter">, I haven't tried Elodea, but it may well work as a food as it begins to decompose. They like dried Nettle leaves, Kale, Spinach etc but you need to leave them in the tank until they begin to go slimy.

Unless you have a huge tank for long term success you need to get them to feed on an alternative food source (still low in nutrients, I feed mine Bell Pepper, Courgette and Cucumber) and then they will begin to show more natural behaviour, where they spend a lot of time resting on Echinodorus leaves etc. (often communally) and become active in the evening and over night.

cheers Darrel
 

Sacha

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Thanks for the info Darrel. What's the best way to supplement their diet then, kale and spinach? Do you blanch it first or just chuck it in raw?
 

dw1305

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Hi all,
What's the best way to supplement their diet then, kale and spinach? Do you blanch it first or just chuck it in raw?
Blanch it, it just helps it break down a bit quicker. I have dead leaves in all the tanks, but the leafier vegetables need to be off the bottom if you have snails.

I don't bother blanching the courgette, pepper or cucumber, but I have a lot of snails so the vegetable surface is rapidly eroded. I fasten the slices of vegetables about 2/3 up an upright bamboo cane (just with an elastic band), and put it in the flow, this keeps some of the smaller snails off, but usually I have to replace them every couple of days.

There are quite lot of threads on the Loricariid forum of "PlanetCatfish" about feeding adults (and fry) of a range of "vegetarian" plecs, including Otocinclus.

cheers Darrel
 
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Otocinclus are adapted to survive in low oxygen conditions, because they gulp air but if you see them gulp air often, there's something wrong going on in the tank. I've seen a video of them about some of their natural habitats, alongside corydoras, the only ones surviving the dry season and appalling water conditions due to them being capable of gulping air at the surface. So they are quite hardy that way but one shouldn't have "a dry season" in their tanks at any stage. The rest of the fish will suffer faster for sure.

My common pleco got stressed when I overdosed with liquid carbon, he'd gulp air several times a day and he doesn't do it at all normally. So they may get stressed by various factors. He'd also gulp air during a water change and I do 50% at a time and my tap water is saturated with CO2. I don't know if that plays a role in the gulping or it's the actual fact all filtration is off during a water change but I always have an air stone running all the time.

I'd imagine injected CO2 at high levels are a different ball game and some fish are less tolerant than others and it has nothing to do with oxygen content. They may not even gulp air but just stay lethargic instead.

My ottos will not try eating vegetables if there's enough suitable algae in the tanks. But then again 4 of mine are in a 90G tank and they always seem to find something. My other 3 are pretty much to themselves in a 120 litre with a few kuhli loaches that don't compete with them for food and cherry shrimp. My baby otto, who I raised on zucchini, has not been seen touching zucchini after the first couple of months. I am guessing he prefers other food available in the tank. In this tank, they do go for spirulina sticks from time to time, or at least gather alongside the shrimp when I drop this food so I am guessing they are attracted to it. I do drop veg at least once a week, they don't touch it at all....But my guess is hungry ottos will.
I also have leaf litter in that tank constantly so as Darrel suggests that maybe helping along.
 
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