Is otocinclus' dependence on symbiotic gut bacteria actually a real thing?

[Chloe and Speckles]

Hi all, new member here! I was just wondering, I've read and been told that it is common for otocinclus to die within the first few weeks of arriving home. I know on Aquarium Co Op the reason stated is that once otos are starved beyond a certain point they lose their appetite and then they're as good as dead. However, another reason I've heard online for this is that otocinclus rely on a symbiotic relationship with gut bacteria, and during shipping (slash time at neglectful pet stores) the gut bacteria can die off if they're starved for too long. So apparently even when they come home and they're eating the food you give them, since their gut bacteria died off they can't actually digest the food they're eating, and they die. They're full but at the same time they're unable to absorb any of the nutrition, so they starve and die. I have found lots of people on forums and care guides stating this, but I've tried and tried and haven't found any scientific papers or been able to find who actually discovered this about otos. I was just wondering if any of you know of the source of the knowledge that otocinclus rely on a symbiotic relationship with a bacteria in their gut to digest their food? A lot of you are so much more experienced than I am, am I just looking in the wrong places?  At this point I'm starting to question whether someone just made this up to account for mysterious deaths in the first few weeks of bringing otos home, and then it just caught on because people accepted it at face value. 

[DannyBWell]

I've always heard it's because they're starved most the time and only to buy ones with nice pearl shaped tummies 

[xXInkedPhoenixX]

While I have no scientific way to tell you this is true, it has been my experience. My original set did NOT lose their appetite, in fact they ate almost all my diatom algae before they started passing away 1 by 1. It makes sense that the bacteria in their gut dies off when they don't eat and they can't regain the population and therefore pass. The LFS I bought them from told me they died because my water is too cold and I needed a heater. This is simply not true in the end. One of those original made it and I believe the one that did was female and ended up being my Momma Oto, later I added 7 more Otos from a different LFS and they all made it (still didn't have a heater, so there other LFS). 

[Drew Schmidt]

On 7/14/2021 at 9:20 PM, Chloe and Speckles said:

Hi all, new member here! I was just wondering, I've read and been told that it is common for otocinclus to die within the first few weeks of arriving home. I know on Aquarium Co Op the reason stated is that once otos are starved beyond a certain point they lose their appetite and then they're as good as dead. However, another reason I've heard online for this is that otocinclus rely on a symbiotic relationship with gut bacteria, and during shipping (slash time at neglectful pet stores) the gut bacteria can die off if they're starved for too long. So apparently even when they come home and they're eating the food you give them, since their gut bacteria died off they can't actually digest the food they're eating, and they die. They're full but at the same time they're unable to absorb any of the nutrition, so they starve and die. I have found lots of people on forums and care guides stating this, but I've tried and tried and haven't found any scientific papers or been able to find who actually discovered this about otos. I was just wondering if any of you know of the source of the knowledge that otocinclus rely on a symbiotic relationship with a bacteria in their gut to digest their food? A lot of you are so much more experienced than I am, am I just looking in the wrong places?  At this point I'm starting to question whether someone just made this up to account for mysterious deaths in the first few weeks of bringing otos home, and then it just caught on because people accepted it at face value. 

I’ve never heard of the gut fauna theory. I’ve always been told it’s because when they are collected they use chemicals that basically incapacitates then makes them float to the surface for easy collecting. I’ve heard it can cause gill and intestinal damage. 

[Chloe and Speckles]

On 7/15/2021 at 1:45 PM, Drew Schmidt said:

I’ve never heard of the gut fauna theory. I’ve always been told it’s because when they are collected they use chemicals that basically incapacitates then makes them float to the surface for easy collecting. I’ve heard it can cause gill and intestinal damage. 

Gasp that's terrible!!

[Chloe and Speckles]

On 7/15/2021 at 1:37 PM, xXInkedPhoenixX said:

While I have no scientific way to tell you this is true, it has been my experience. My original set did NOT lose their appetite, in fact they ate almost all my diatom algae before they started passing away 1 by 1. It makes sense that the bacteria in their gut dies off when they don't eat and they can't regain the population and therefore pass. The LFS I bought them from told me they died because my water is too cold and I needed a heater. This is simply not true in the end. One of those original made it and I believe the one that did was female and ended up being my Momma Oto, later I added 7 more Otos from a different LFS and they all made it (still didn't have a heater, so there other LFS). 

That's interesting that some of yours died even though they had full bellies, I hope mine don't die off inexplicably too. Awwww Momma Oto was the one that survived, what an awesome fish. Who knew she'd go on to produce 30+ babies!! And pshh, good thing you have another LFS option. 

[gardenman]

On 7/15/2021 at 9:33 AM, Chloe and Speckles said:

Gasp that's terrible!!

Fish collecting isn't always all sunshine and rainbows. If you've ever tried to catch an oto in a tank you can imagine how hard it is to catch them in the wild. The use of poisons and anesthetics is pretty commonplace (also with marine fish where cyanide is often used to catch reef fish.) The poisons/anesthetics will disable the fish and they float to the surface for easy capture, then into freshwater to try and revive them.  Some people use electric shock to stun fish to make them easy to capture. It's called electrofishing.  For small, fast-moving, bottom hugging fish like otos, conventional seine nets are pretty much useless to catch them in the wild. When you look at the price of an oto (typically under $5 here) and realize that they were wild caught, flown halfway around the world, went through an importer, wholesaler, local distributor and finally the pet shop and still retailed for under $5, they had to be caught in large numbers and fairly easily. The only real way to do that is by using poisons and anesthetics to bring a lot to the surface for easy collection at one time.

[Chloe and Speckles]

On 7/16/2021 at 12:41 AM, gardenman said:

Fish collecting isn't always all sunshine and rainbows. If you've ever tried to catch an oto in a tank you can imagine how hard it is to catch them in the wild. The use of poisons and anesthetics is pretty commonplace (also with marine fish where cyanide is often used to catch reef fish.) The poisons/anesthetics will disable the fish and they float to the surface for easy capture, then into freshwater to try and revive them.  Some people use electric shock to stun fish to make them easy to capture. It's called electrofishing.  For small, fast-moving, bottom hugging fish like otos, conventional seine nets are pretty much useless to catch them in the wild. When you look at the price of an oto (typically under $5 here) and realize that they were wild caught, flown halfway around the world, went through an importer, wholesaler, local distributor and finally the pet shop and still retailed for under $5, they had to be caught in large numbers and fairly easily. The only real way to do that is by using poisons and anesthetics to bring a lot to the surface for easy collection at one time.

Wow. I hope someone figures out how to breed otocinclus, and lots of other species of fish, en masse in captivity so that fish don't need to be poisoned and starved.