Communication Bars.

#1
Hello,

During a conversation with Alan (Alsbeth on here) he mentioned the barring on Altums and possible changes that take place. With Discus the so called "Stress Bars" (I dont like that term and call them communication bars) change regularly and for many reasons, for example, water conditions, feeding, spawning etc.

Does the same thing happen with Altums and other Angels and to what extent? What are peoples observations with this? Obviously with Discus its quite extreme from Black to almost white.

Dan
http://www.youtube.com/user/dans2727

re: Communication Bars.

#2
Hi Dan
With Scalares and Leopoldi I find generally the stripes tend to be rather more of a fixed item than with discus.

Whereas discus change by the minute, and certainly communicate much by their bars, the angels I have and have kept in the past seem to use them more as a camouflage instrument.

Once I had a tank of scalares in a very light tank, and the whole bunch of them faded their bars and scarcely showed them at all.

The very silvery body of angels, which reflects the surrounding colours, and the stripes, seem to me to create a sort of disruptive / broken appearance. I guess a sort of stealth pattern.

On the other hand with discus, the barring seems to make them less stealthy looking when it intensifies or shows strongly, and also it can often be a sign of a stressed fish.

Can't really say about altums, never having kept them.

When angels are showing off to each other there can be an intensification of the striping, but that seems to be a lesser characteristic than with discus.

Alec

re: Communication Bars.

#4
In P. altum we have what I will call foreground bars and backgound bars. And if any member feels they can better describe the bars by another term, please let us know.

The foreground bars are the normally darker, dominant bars that occur in an odd number sequence beginning by the one that vertically crosses the eye (1st) and then the 3rd, 5th and 7th (the latter over the caudal peduncle).

The background bars are lighter, but evident, over the altum's silver body and occur in even sequence, 2nd, 4th and 6th (tle latter just before the caudal peduncle foreground bar).

Healthy altum kept in an aquarium will generally exhibit foreground bars which are light brown to dark brown in color. The background bars may not be evident at times.

When the fish are nervous or simply not so comfortable, the foreground bars can be very light and most likely you will not see the background bars. The silver base color of the body predominates and the foreground bars are seen as a mere translucent brown overcast. In this condition, P. altum will show virtually no red pigmentation.

When the fish are better acclimated and fed, the bars will have a rich mahogany red/brown to dark chocolate brown, and the background bars will be very evident as a translucent brown shadow over the silver body base. You can see a clear silver borderline running vertically between each foreground and each background bar.

When the fish is stressed or ill, the foreground bars will become very dark, and the background bars will also be relatively dark. The brownish color will tend to blacken up and the the fish lose all reds and dull into gray tones. In this case there is much less a difference in intensity between the fore and background bars, though usually a difference is still evident.

When aroused, courting or defending territory or their spawn, the foreground bars pick up an intense black or very dark black coffee tone, the background bars will take a pink to translucent light red/brown cast.

Full red eyes only show in altums when in prime condition. Half red eye and the fish are doing very well, no red and well, they're just normal.

The head and dorsal area in healthy P. altum are adorned with a turquoise iridescence and red spotting. Red and blue striations can radiate into the fins.
Regards
Ed
God listens. He may not always give you everything you want, when you want it; but he always gives you what you really need, when you need it most!
E.R.

re: Communication Bars.

#7
I have never seen red eyes in juveniles, never seen full red eyes in subadults (only half red at best). This would make me think that is has something to do with maturity. But not all mature altum show the full or even half red eye.
Ed
God listens. He may not always give you everything you want, when you want it; but he always gives you what you really need, when you need it most!
E.R.

re: Communication Bars.

#8
That's is right, from my observations of my altum.

The red coloration and marks on their nape area, the blue/green sheen, the reddish color of theirs fins extensions are signs of them becoming young adults.

The eyes red coloration happens on the posterior side of the eyes and is about 1/4th to 1/3rd of the circunference. I became to notice this in my altums when they were around 10 months, or so, old.

About the bars, the main 4 are those that have the dark brown/black coloration, the other 3 alternating, and lighter brown bars are more evident on very juvenile and young specimens and they have the tendency to be less evident/visible as the altums mature. Also when the altums are under stress they tend to show better.

IMHO, nature being efficient and simple, the bars serve for comouflage as well as to communicate among them.

Eduar
Last edited by Acualtum on Tue Aug 24, 2010 3:07 pm, edited 1 time in total.
http://worldviewofglobalwarming.org/
http://www.sciencedaily.com/releases/20 ... 132656.htm

re: Communication Bars.

#9
I should say that I spent a whole day swimming right in front of a school of altum, no more than 6-8 feet away at times, and I did not see them. I concentrated on the M. insignis, Prochilodus, tetras and other fish.
I called Wil that night and told him I was at Pozo Azul (20 min.North of Puerto Ayacucho) and he asked me if I had caught any altum. I said no, I did not see one. He told me where to look.
The next day I went there again and right where I had spent most of the time under water the previous day, there they were, among the branches. The silver reflecting the sand and stones, camouflaging the body against the background, the brown bars vanishing among the submerged tree branches. Circa 1980.
Ed
God listens. He may not always give you everything you want, when you want it; but he always gives you what you really need, when you need it most!
E.R.

re: Communication Bars.

#12
I have noted the following variations in baring patterns in my Pterophylum at night:

In Peruvians the fifth bar remains dark the other oddd numbered bars fade. The evens arn't really visible.

In altums the pattern fits Ed's description of stress coloration ie both odd & even bars are dark but there remains a definite difference between the even (background) and odd bars.

In silver pearlscale domestics the typical scalare daytime patterns seem unchanged.

In my zebra domestic the bars all fade equally and the body is more washed out. This mutation can be seen as one in which the ability to differentially fade or heighten bars has been lost.


I suggest we can view the altum vs scalare barring patterns as indicative of two different camouflage strategies. Scalare employs a disruptive coloration tactic (the zebra (four legged type) strategy). The smaller number of black bars contrasting with a highly reflective body thereby breaking up the body outline effectively even in clear waters. Altum darkens the thick even numbered bars when threatened and the remaining body is also less brightly reflective. The overall somewhat muddy (sorry altumphiles) colouration would seem to be optimized for fading into the murky-tea colur blackwater streams of the Orinoco. It's a "match to background" camouflage tactic.

Dennis

re: Crown irridescence in altum

#13
My mature altums and many others seen in photos have an area of blue irridescence in the crown area just in front of, and extending into the front of the dorsal fin. Red scales are sprinkled in this irridescent area. I think I've seen some scalares with this trait but I'm not sure and my own lack any hint of it. At any rate at night and under some alarm the pattern completely vanishes in my fish.

Dennis

re: Communication Bars.

#15
Dan, I think that if the background and substrate are change or the fish have been moved to a new tank/miliue they will react to the changes/stresses by changing their coloration. Ususally their color become lighter. Once they get used to their new surroundings the normal coloration returns. When the fish are ill, usually, they become darker in their overall coloration.

That generally was my experience with my altums, the few times I did move them around. And, again, once they get used to the new set up the normal colors returned. The only variation would be if the tank where they were had more green and brown colors, the coloration of the fish would be darker due to the darker colors reflecting less light off them. When I moved them to the 100g tank without gravel and blue sky color background, then, they would look with lighter averall. Also the intensity of the lights affects the way they look.

Eduar
http://worldviewofglobalwarming.org/
http://www.sciencedaily.com/releases/20 ... 132656.htm
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