Fish which need driftwood.

[coyotethug]

I had a large piece of malaysian driftwood that had a tunnel in in. My plecos (royal, rhino, bushy nosed, blue panaque, queen arabesque) all devoured the wood. It was reduced to 25% of its original mass in 2 years, thats about 20 lbs of wood eaten.

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[RD.]

So the wood itself it just a means to an end really.

I believe so.

Scraping/sucking on everything in a tank is simply a natural feed mechanism for most plecos, some more than others. Remove the wood & replace it with something else, and they will work that over just as efficiently as they did the wood. I have plastic pieces of bark/driftwood from qt tanks that have been stripped of the finish by plecos. I stopped using them as I was concerned about the fish ingesting the painted finish. I'm pretty sure when the manufacturer stated "aquarium safe" that's not what they had in mind. lol

 

[Dan F]

Plecos do not require wood as part of their diet, nor can they digest it.

http://www.monsterfishkeepers.com/forums/showthread.php?509614-Can-Plecos-Digest-Wood

From the article you linked to:

'I think that the answer to the question "Do they NEED to EAT wood" may actually be "yes", because that is what they do in nature.'

So, according to the expert you cited, the statement "Plecos do not require wood as part of their diet" may not be 100% accurate?

The article also stated that plecos do, in fact, digest wood. They do not digest it efficiently enough to live on an all-wood diet, but they absolutely do digest cellulose - between ~23% and 32% of what they eat. It also stated that about 70% of their diet in the wild is wood.

I really don't see how you can cite that paper as proof that plecos don't need wood or that they can't digest it....

 

[RD.]

Dan - there is no doubt that fiber is beneficial to many species of fish, including most if not all species of plecos. But fiber can be gleaned from many feed stuffs, there is no specific dietary requirement for a pleco to eat wood. They are drawn to wood due to thousands of years of being hard wired to do just that, no other reason.

The main point being wood is not digested by plecos, they simply do not have the enzymes to assimilate wood. This is & has been a common misconception held by many in the hobby for decades.

Do I add wood to my tanks with plecos - why yes I do, as I personally like the aesthetics of a tank that is aquascaped with driftwood, if it's appropriate to the geographical location of the fish.

 

[Jc1119]

"Along with the species of the Hypostomus cochliodon group (formerly the genus Cochliodon), it has been argued that Panaque are the only fish that can eat and digest wood.[5] These fish have particular adaptations to its wood diet include spoon-shaped, scraper-like teeth and highly angled jaws to chisel wood.[5] Researchers have also identified symbiotic gut bacteria that may allow the fish to digest the wood they consume.[6] However, others have argued that Panaque do not in fact digest wood, and in fact take up very little energy from the wood they consume and actually lose weight when fed just wood.[7] Furthermore, their digestive tracts are no different from those of related catfish and they do not hold wood particles in the gut longer than other catfish, suggesting Panaque are not phyisically adapted to eating wood, and are in fact detritivores much like other Loricariidae.[7] In September 2010 scientists from the US National Science Foundation claimed to have discovered a new species of wood-eating catfish in the Alto Purús National Park, Peru.[8]
[edit]

http://en.wikipedia.org/wiki/Panaque

interesting

 

[Dan F]

Dan - there is no doubt that fiber is beneficial to many species of fish, including most if not all species of plecos. But fiber can be gleaned from many feed stuffs, there is no specific dietary requirement for a pleco to eat wood. They are drawn to wood due to thousands of years of being hard wired to do just that, no other reason.

The main point being wood is not digested by plecos, they simply do not have the enzymes to assimilate wood. This is & has been a common misconception held by many in the hobby for decades.

Do I add wood to my tanks with plecos - why yes I do, as I personally like the aesthetics of a tank that is aquascaped with driftwood, if it's appropriate to the geographical location of the fish.

By the way, those are great articles you linked to, very interesting. I love the word 'xylivore'.

I get what you mean, cellulose is cellulose, no matter what the source.

The main problem I can see with keeping wood-eating panaques in a tank with no wood is that very few food products are going to give them the high levels of cellulose in their diets that they are evolved to consume. If 70% of their intake is wood and they are digesting ~30% of that cellulose, then they are actually getting a quite significant portion of their dietary intake from wood. I doubt many prepared foods contain that level of fiber?


Of course you don't "need" to have wood in their tanks to grow and thrive - we have all seen beautiful photos of fish raised on dog food and hot-dogs, but I think most of us strive to recreate natural living conditions to some degree if possible. The one advantage I can see to not giving them wood to eat is that you won't fill your tank with the huge amounts of undigested sawdust that they poop out....

 

[Dan F]

Back to the O.P.'s original question, another fish that really love to scrape on driftwood is a Flagtail (Prochilodus). I have a lot (maybe 60-70 pounds) of grape wood in my tank and my Flagtail keeps it nice and clean.

 

[RD.]

The OP's question was answered on page 1, his fish do not require driftwood in their tank.


And Dan, the fact that a fish has evolved to consume (fill in the blank) doesn't necessarily equate to that fish requiring that level of (fill in the blank) when kept in captivity. One is only fooling themselves if they feel that by supplying wood to a panaques tank that they are somehow replicating what takes place in nature. This would be the same as growing algae on rocks in an aquarium & assuming that would be replicating what a Tropheus consumes in the wild.

Feeding a lower volume of fiber content to a pleco isn't even remotely close to those who feed dog food and/or hot dogs to their fish. That was a rather poor comparison.

I have no issue with anyone using driftwood in their tanks, with or without plecos, as previously stated, I myself do. Having said that, according to the most recent science that is available - wood has not been proven to be a dietary requirement for plecos kept in captivity, furthermore it appears that plecos do not have the correct enzymes to even digest wood. Does the extra fiber from driftwood aid in their overall health & well being? That could depend on a number of factors, including but not limited to what the rest of their daily diet consists of.

 

[Dan F]

The OP's question was answered on page 1, his fish do not require driftwood in their tank.


And Dan, the fact that a fish has evolved to consume (fill in the blank) doesn't necessarily equate to that fish requiring that level of (fill in the blank) when kept in captivity. One is only fooling themselves if they feel that by supplying wood to a panaques tank that they are somehow replicating what takes place in nature. This would be the same as growing algae on rocks in an aquarium & assuming that would be replicating what a Tropheus consumes in the wild.

Feeding a lower volume of fiber content to a pleco isn't even remotely close to those who feed dog food and/or hot dogs to their fish. That was a rather poor comparison.

I have no issue with anyone using driftwood in their tanks, with or without plecos, as previously stated, I myself do. Having said that, according to the most recent science that is available - wood has not been proven to be a dietary requirement for plecos kept in captivity, furthermore it appears that plecos do not have the correct enzymes to even digest wood. Does the extra fiber from driftwood aid in their overall health & well being? That could depend on a number of factors, including but not limited to what the rest of their daily diet consists of.

I am sorry to drag this out, but I just find it very strange that, in the papers cited by you, the author states that he believes plecos do "NEED to EAT wood" and that they do digest cellulose at a rate that is approximately half as efficient as a porcupine, the quintessential xylivore. Whether they digest lignin is in question, but actually the research in the linked paper supported the hypothesis that they do. The author did say that the apparent metabolization of lignin could be an error due to flawed methodology, but did not say that lignin digestion is not occurring. Did you read the entire article?

You state unequivocally that wood is not needed in their diet and that it is not digestible, but the research that is supposedly backing up thee claims says just the opposite.

Do you have some other more recent scientific studies that you are going off here?

Also, this is still page one for me, 40 posts per page is the only way to go!

 

[RD.]

The first point I would like to make is that I DO NOT like the title of the interview. "Do catfishes need to eat wood?" I would answer that question differently than those that they asked. If you read my articles, you will see that the fish do indeed ingest wood in the wild, and this is very much part of their natural niche. So, I would rather ask the question: Can wood-eating catfishes digest wood? I think that the answer to the question "Do they NEED to EAT wood" may actually be "yes", because that is what they do in nature. What they get nutritionally from the wood is a different question altogether (see below).

That's the direct quote. The fact that a fish does something in nature doesn't equate to one having to replicate that behaviour and/or feeding strategy in captivity. The author was adding his personal opinion on the subject during an interview, that clearly had nothing to do with the results found during his feed trial in the paper below. (and yes, I read the entire article shortly after it was released)

Also during that interview with Matte Clarke, Donovan German stated;

Fifth, the difference between the words “eat” and “digest” must be defined. “Eat” means to consume. That is it. The word “eat” does not imply that whatever was consumed can be digested and utilized in a nutritional manner by an animal. The word “digest” implies that what was eaten can be broken down (i.e., digested) by hydrolytic enzymes in the GI tract of an animal and absorbed for use in a nutritional context. To use these two words in a real life example: Parrotfishes eat coral. There is no denying that the parrotfishes consume a considerable amount of coral (and by this I mean the hard, calcium carbonate reef); gut content analyses show that the fish eat coral. However, parrotfishes do not only eat coral, and they certainly do not digest coral in their guts. There simply isn’t any nutritional value to carbonates. Many parrotfishes are actually detritivores, taking bites of reef to access the nutritional detritus that has collected in the interstitial spaces of the reef (Crossman et al. 2005). Much in the same way, the wood-eating catfishes “eat” a considerable amount of wood (~70% of their intake). However, they poorly “digest” the bulk wood (the cellulose and lignin of the wood proper), but efficiently digest detritus and wood degradation products (e.g., disaccharides). I hope this analogy helps. Wood is the reef in the Amazon, providing critical habitat to so many fish species.

Wood-eating catfishes, therefore, are the parrotfish of the Amazon, not the beavers of the fish world (as I commonly end my talks). I just want to make it clear that I never said that Panaque do not “eat” wood. They certainly do. The wood-eating catfishes just poorly “digest” wood itself.

Back to the paper .......


http://german.bio.uci.edu/images/PDF/German (2009) JCPb_gut_print.pdf

That's the paper that I linked to, which also seems pretty clear on the matter. See direct quotes below.

Discussion

The data gathered in this study clearly support the null hypothesis that the “xylivorous” loricariid catfishes do not efficiently digest the fibrous components of wood in their GI tracts.

Each of the analyses provided evidence that the fishes do not exhibit specialized gut anatomy for harboring endosymbionts: no kinks, valves, or ceca are present anywhere along their long, narrow intestines; the MVSA
decreases distally in the intestine, indicating that most absorption takes place in the proximal and mid-intestine; no conglomerations of microbes were observed in the SEM or TEM micrographs; the fishes pass wood through the gut too quickly (<4 h) for microbial digestion of cellulose; and the fishes do not retain small particles anywhere along their digestive tract.

Furthermore, the catfishes were unable to digest wood and thrive on it in the laboratory. Each of these components would be expected to be the opposite in an animal that digests wood via an endosymbiotic community of
microbes living in their GI tract.

However, loricariid catfishes certainly have interesting digestive tracts (the longest among all fishes measured to date; Horn 1989, Kramer and Bryant 1995) and subsist on detritus in the wild, which they appear suited to digest (Bowen et al. 1995; German 2009; German et al. 2009).

There has been some debate over the last 15 years as to whether xylivorous catfishes can digest wood. Schaefer and Stewart (1993) suggested that species in the genus Panaque &#8220;could be capable of extracting energy from wood&#8221; and this assertion has been assumed to be true ever since, especially on the internet and among aquarium fish enthusiasts.

However, the one study published to date examining digestion in species of Panaque and Pterygoplichthys provided only inferential evidence of cellulose digestion (Nelson et al. 1999). The data gathered in the current study and that of German and Bittong (2009) systematically refute that wood-eating species in the genera Panaque or Hypostomus, or the detritivorous Pt. disjunctivus, have the capability to digest and subsist on wood.

The total digestibility of the fiber content in the wood was extremely LOW, so low that as far as nutrient value I personally would dismiss any type of importance entirely. As stated previously, fiber can be gleaned from many feed stuffs, there is no specific dietary requirement for a pleco to eat wood. They are drawn to wood due to thousands of years of being hard wired to do just that, no other reason.



I keep fish that in nature are known to eat live frogs, lizards, and fish - yet I do not feed them any of those foods, nor would I even if those foodstuffs were easy & affordable for me to secure. Do my fish suffer from that? From a nutritional stand point, no more than a panaque would that was raised on a balanced diet (including fiber) that didn't include wood.