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Posted: Fri Jan 13, 2006 4:29 pm
by Tony T.
Hendra wrote:Try after the tutorial from Martin, thanks
New home for
Gastromyzon sp SK01
In these pics what are those tiny white spots all over the body? From the front they seem to rise out away from the skin [similar to tubercles or papillae?].
Posted: Sat Jan 14, 2006 11:55 am
by Hendra
I believe the white (little) spots is tubercles
Posted: Sat Jan 14, 2006 12:04 pm
by Graeme Robson
Superb!!
Graeme.
Posted: Sun Jan 15, 2006 10:38 am
by Tony T.
Thanks. Make me wonder do tubercles appear on other Gastromyzon species?
Posted: Tue Jan 17, 2006 5:08 am
by Hendra
I think tubercles also found at another species of
Gastromyzon, esspecially at snout and dorsal part of head of mature specimens. In Inger and Chin paper (about
Gastromyzon spp), all described species have tubercles.
If you interested I can send you the file.
Posted: Tue Jan 17, 2006 11:46 am
by Tony T.
I send you PM for detail so please check
Posted: Tue Jan 17, 2006 11:58 am
by Martin Thoene
OK guys, time for out-of-the-box thinking again. In my Hillstream article I go a lot into my personal theories on the body shape of these fish. Reading information on aerodynamics leads me to believe that all these sucker-type fish have body shapes honed to produce an effect in fast flowing water.
Theoretically, you would think that the smoother the fish's body was the "slipperier" it would be in the water flow right? Same thing with planes....smoooooth. Except there are some aircraft that have some weird detailing on their wing surfaces........
This is a Gloucester Javelin. The small vertcal protrusions on the wing's upper surface are known as "Vortex Generators". Each one creates small vortices of air over the wing and increases the speed of the laminar flow across the suface. Effectively, this helps with wing lift at high angles of attack, but also increases the air retention to the shape of the wing, increasing control for the pilot. The air more closely follows the aerodynamic shape of the plane.
Now if you look at a
Gastromyzon compared to a
Beaufortia......
Gastromyzon are a lot "taller" in profile than a
Beaufortia. Maybe the water flows over Beaufortia easier because of the low-profile, effectively a low chord wing shape?
Gastromyzon are of a heavier chord shape (i.e. thicker cross-section in profile) and maybe this creates a laminar flow seperation? By having little "bumps" on the body I would theorize that they must create vortices and force water to cling more to the shape, ultimately exiting behind the fish with less drag and tending therefore to lessen the tendency to move the fish from its intended resting place.
You can get weird effects from dimples rather than protrusions too.....golfballs.....
http://www.aerospaceweb.org/question/ae ... 0215.shtml
I get up close and personal with vortex generators almost every working day. I do a lot of refuelling on Cessna 172s and 182s with them fitted.
The fuel filler is just out of picture on the right.
Anyhow, that's my 50c. They may have a biological function in
Gastromyzon (don't know what) but my bet is they are of aero (read hydro) dynamic benefit.
Martin.
Posted: Tue Jan 17, 2006 12:25 pm
by Tony T.
It depends on whether or not both sex of Gastromyzon have similar tuberculation pattern. For some cyprinids such as Barilius and Zacco only males have large and numerous tubercles while females have much less, and they are known to fight other males a lot, often violently. In this case it can be easily seen that tubercles are used for fights.
Posted: Tue Jan 17, 2006 1:00 pm
by Martin Thoene
Tony T. wrote:It depends on whether or not both sex of Gastromyzon have similar tuberculation pattern. For some cyprinids such as Barilius and Zacco only males have large and numerous tubercles while females have much less, and they are known to fight other males a lot, often violently. In this case it can be easily seen that tubercles are used for fights.
Inger and Chin, 1961 quotes various species having tubercules, some definitely nuptial in nature around the head area. These tend to be bigger in males during breeding activity and in some females present or absent.
I'm looking at these body tubercules as something different. Based on what i know and see of
Gastromyzon territorial battles there's no real use of these features as weapons.
Head tubercules, particularly in
Pseudogastromyzon seem to have great significance because it's always the male with the best "rack" that seems to be the one breeding in an aquarium environment. He is dominant by his obvious "maleness" and is the one that the females choose to mate with. I've seen sub-dominant males doing courship dances with females, but never seen one be accepted. They always go for the best looker.
Martin.
Posted: Thu Jan 19, 2006 10:47 am
by Tony T.
Do females in OD have body tubercles too? It would be interesting if such swimming aid is missing on one sex.
On the other hand maybe for hillstream loaches tubercles are more for display than actual use? In Schistura I had seen males with enlarged cheek use their cheeks to hammer their opponents during disputes of similar species, so we know at least one use of the enlarged cheeks i males. Schistura fights can be quite violent, however, with actual damage on both side.
Posted: Thu Jan 19, 2006 10:53 am
by mamaschild
Absolutely gorgeous loaches
If I could talk my hubby into having a tank with just rocks in it and not full of plants, I would definately have a bunch of these guys. I love the way they swim, and the patterns I've been seeing lately are wonderful.
Wow!
Posted: Thu Jan 19, 2006 9:46 pm
by cybermeez
Nice chubby Hillstreams! That Kalimantan Gastro is stunning!
Posted: Sun Jan 22, 2006 1:18 pm
by Hendra
My first concept is to replicate the natural habitat of them, there is no any waterplants found in
Gastromyzon spp niche since the water very rapid, but I got a nice experience from adding some plants in Gastro tank yesterday.
Casually, I added some
Piptospatha grabowskii in one of my river tank, the plants is from another (planted) tank which was my first river tank ( I already remove the R/T manifold and changed the setting to be just planted tank ). Since the plants have algae at the surface of the leafs, some
Gastromyzon didn’t want to neglecting the chance to got some yummy vegetable snack since they only consume bloodworms everyday.
They look quite happy with the vegetables, so I try to put a small rock (from another tank) which have green algae at its surface in
Gastromyzon tank. After several time I found the surface of the rock become clean, only small amount of algae left.
Pic of comparison between the “clean” rock and algae rock.
So, I put a bigger rock. The result is ALL
Gastromyzon sp. come together to this rock and its become an “algae party”.
The party move from the right algae rock (the same rock with little “clean” rock in pic above) to the left one.
View from top.
Another “Sunday Algae Party” at another tank.
This experience give me an idea to make algae culture, perhaps some rocks in water container, with the help of sunlight can provide nice foods for
Gastromyzon spp.
The tank where the plants and rocks come from. Have planning to re-setting the layout with some driftwoods.
Posted: Sun Jan 22, 2006 1:28 pm
by Mike Ophir
beautiful photographs....all the more reason to get a big river tank!
Mike
Posted: Sun Jan 22, 2006 1:34 pm
by shari
Very cool party!