Dillema - What are the Ls real water requirements

[bigbird]

Hello Members,

My interest was raised, when I read the mail from Silverdub http://www.plecoplanet.com/forum/showthread.php?t=14214
where the dream was to create a biotope from Xingu and Altameira. I loved the photos and images of the natural landscape and underwater shots. However I ask myself, unless you buy wild Ls, how do others Ls know what conditions they like. IE L282s need fast water L138 needs slow water. Now before I continue I do not wish to contradict anybody, but surely data of water current and flow must be from wild caught Ls ? Take the classic stunner L333. According to all references, they like fast flowing water. My deep and meaningfull question is what about 8 or 10 generations of Ls that have been bred in captivity, do they know what stimulates them or what their needs are or does Darwins theory come into play. IE in SYD I buy fry off a seller at -5 cm, these fry are 9 or 10 generation from their adults bred under different conditions etc. How would I know what their needs are ?
Now please do not get me wrong, I value my Ls and will give them a gold glove treatment to make sure that they are fine, but this question intrigues me a lot. Do you try and mimic the conditions of the wild, knowing that they are 9 or 12 generations from the origininal wild parents or / and they these new fry are commercially bred ?

Just a thought ?
cheers jk :thumbup:

 

[zeebo]

humm ,this is a very interesting and worthy consideration . not sure of the answer. I am not familiar with tank bred plecs ,so i would ask from your question if generations of tank bred plecs still act as the wild caught, ie: do they stay hidden all day from us, eat only at night, cave , ya know ,stuff that they were naturally wired for in the beginning? If all that behavior remains , I would have to wonder what else remains and what they have adapted to ,being born in a tank.

Great question BB, and understand why you are asking. Hope to hear others
observations on this

Georgie

 

[Lornek8]

First off, there is no way they are 9-10 generations removed from the wild. More likely 3 possibly 4 tops. L333 was assigned around 2003, about 9 years ago. If you were able to get them from egg to spawn in 1 year, maybe you'd get 9 generations, but that's even difficult with Ancistrus let alone Hypancistrus.

Even at that, 9 years or so & 3-4 generations is hardly a speck in the evolutionary development of the species. Best would be to imitate as best as possible the requirements of the wild fish.

 

[bigbird]

yup ok for that, I do try to mimic the best conditions for them, but was just wondering, especially in Europe where Ls have been for a long time. cheers jk :thumbup:

 

[Lornek8]

L001 was assigned in 1988. The big influx of L#s didn't really occur until the early 90's so there really haven't been many plecs in captivity for countless generations. There were a few kept since the 60s but most were not bred and were simpy viewed as cleanup crews. It wasn't until the L# craze that much effort was put into breeding plecs. Zebras were one of the early L#s and Hypancistrus are one of the more commonly bred plecs but you'd be hard pressed to find many F4s or F5s. They were assigned in 1989 but I don't think they were first bred until about 92 or 93, I think I still have the TFH with the breeding description somewhere. So really, a long time in captivity for a L# is still relatively short.

 

[bigbird]

thanks for that, learnt something new. cheers jk :thumbup:

 

[dw1305]

Hi all,
Easiest way to work out whether a fish comes from fast flowing water is its shape and morphology. If you have a flat, streamlined, tear-drop shaped fish with a big sucker it is almost certainly current loving or "rheophilic", a rheophilic plec "template" is in <http://plecoplanet.com/?page_id=829>, using L235 Pseudolithoxus anthrax as the example.

If you wanted a genus with both rheophilic and non-rheophilic fish Ancistrus would do, with fish like L309 and A. ranunculus the rheophiles.

L309

Habitat and evolution are quite important as rheophilic plecs nearly all have very high oxygen requirements, and Pseudolithoxus, Hypancistrus, Spectracanthicus etc. have lost the accessory blood vessels in the gut that allow some Hypostomus etc. to breathe atmospheric oxygen.

From De Oliviera et al (2001) "Microscopical aspects of accessory air breathing through a modified stomach in the armoured catfish Liposarcus anisitsi (Siluriformes, Loricariidae)." Cytobios. 2001;105(410):153-62

The presence of an accessory air breathing mechanism ... is widespread among Loricariidae, where modified parts of the digestive tract act primarily as oxygen-exchange organs. An anatomical and histological analysis was carried out on the stomach and intestine of the armoured catfish Liposarcus anisitsi. The data support the assumption that the modified stomach is responsible for holding air and allows blood oxygenation under hypoxia. Experiments demonstrating survival of air breathing Liposarcus in severely hypoxic water support the hypothesis and are discussed.

If your plecs are oxygen depleted, they will all come to the water surface and gasp air, suggesting that this gut "lung" was present ancestrally, and has been lost.

The white and clear water rivers normally have very low conductivity values and are very clean (have very low BOD), even if they carry a large sediment load.

If fish are tank bred over generations they may become easier to care for, but only if selection (natural by survival, or man made via selection for fin colour etc) has some genetic variability to begin with. I would be very surprised if there was much genetic variability for oxygen requirement in Loricariids, or tolerance of organic pollution, so I would think that selection is unlikely to make them much more likely to survive low O2 or high NH3/NO2 in the aquarium.

cheers Darrel

 

[jessonthenet]

http://www.britannica.com/EBchecked/topic/328742/laminar-flow

[ame="http://en.wikipedia.org/wiki/Fluid_dynamics"]Fluid dynamics - Wikipedia, the free encyclopedia[/ame]

http://en.wikipedia.org/wiki/Morphology_(biology)

had to bookmark all of this, thanks for that.

Wouldn't a fish have to mutate to become tolerant of its conditions? Is that even possible or is that fish cross breeding with other fish to create new species. One fish is tolerant to water conditions the other fish isn't but the tolerance gene is passed on. Maybe even if the same species breeds together. One may have the tolerance gene and the other doesn't. Is the gene recessive. Genetics is a bit complicated! If fish becomes tolerant was the gene always there but recessive? Just years later 2 fish with recessive genes have bred creating a particular strain and then maybe even inbred. Who knows? I know what I am trying to say but maybe not coming across that well.

 

[dw1305]

Hi all,

Fluid dynamics ... had to bookmark all of this, thanks for that.

You can think of it like aerodynamics on cars. In this case the water is much denser than the air, so you need better streamlining, and the water moves, not the fish. But after that it is the same as a sports car, with minimal ground clearance, wide tyres, a flat under-body and a spoiler on the back, they "suck" the car to the road in the same way the faster, laminar, water flowing under the fish, and over the big stiff angled pectoral fins, sucks the fish to the rock. If you want a really good example of this a Lithoxus spp. shows this really well <http://www.planetcatfish.com/catelog/_species.php?species_id=1334>

Wouldn't a fish have to mutate to become tolerant of its conditions? Is that even possible or is that fish cross breeding with other fish to create new species. One fish is tolerant to water conditions the other fish isn't but the tolerance gene is passed on. Maybe even if the same species breeds together. One may have the tolerance gene and the other doesn't. Is the gene recessive. Genetics is a bit complicated! If fish becomes tolerant was the gene always there but recessive? Just years later 2 fish with recessive genes have bred creating a particular strain and then maybe even inbred. Who knows? I know what I am trying to say but maybe not coming across that well.

No, it does make sense, you can ignore recessive or dominant and just concentrate on whether fish possess the genetic variability (the genes). The quick answer is that crossing species from different genera might be theoretically possible, but it would depend upon how closely related the 2 fish were. If you did have 2 closely related plecs, one with the ability to take in atmospheric oxygen and one without, their off-spring (F1) should have a range of tolerances to lower oxygen, and by selective breeding amongst the F1, F2 etc you could select for those who were most tolerant of lower oxygen levels. If you ignore the "crossing 2 related, but different genera/species", this is what happens to some degree in captivity, and is why wild Discus are more difficult to keep than tank bred strains, which come in a range of colours, etc.

Having said that the chance of being able to breed greater tolerance to low oxygen levels into Hypancistrus spp. etc is so small that you can ignore it. The reason is that the Loricariid catfish have evolved as a huge adaptive radiation, possibly the second greatest evolutionary radiation in the whole of vertebrate evolution (after the Cichlids). They all show certain ancestral features in common - "conserved features" (no scales, same basic body plan) with other ancestral catfish, and other features that differ between genera (dentition, how compressed they are, whether they can breathe oxygen through their stomach lining etc.):

Loricariidae is one of seven families in the superfamily Loricarioidea, along with Amphiliidae, Trichomycteridae, Nematogenyidae, Callichthyidae, Scoloplacidae, and Astroblepidae. Some of these families also exhibit suckermouths or armour, although never together as in Loricariids.

The Callichthydae (Corydoras etc) also breathe oxygen via the gut, suggesting that this is a feature of their mutual ancestor and has been lost by those plecs from highly oxygenated water. Characteristic that have been lost, (like sight and pigment in the Cave tetra) are very unlikely to be regained (this is why Pandas have false thumbs).

cheers Darrel