Explain Piranha Iridescense

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Texas Star

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I'm hoping that Bear Bio or some fisheries biologist can tell me why piranhas and pacus shine with such an iridescent quality, in or out of water. They seem almost to sparkle.

Why? What quality in the scales produces this effect?
 
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I won't be able to sleep tonight until someone explains this.:cool:

One time while Surf Casting for Striped Bass, at about 2:30 AM in complete darkness by myself something weird happened.

Suddenly the salt water began to look really strange to me as I have never seen anything like this. Sort of like being in the twilight zone, but later I found out it was some form of plankton and happens now and then.

Bioluminescent-Plankton-washed-on-shore_zps4f9efed5.jpg


Seriously, I grabbed my gear and left the area that night.
 
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I won't be able to sleep tonight until someone explains this.:cool:

One time while Surf Casting for Striped Bass, at about 2:30 AM in complete darkness by myself something weird happened.

Suddenly the salt water began to look really strange to me as I have never seen anything like this. Sort of like being in the twilight zone, but later I found out it was some form of plankton and happens now and then.

Bioluminescent-Plankton-washed-on-shore_zps4f9efed5.jpg


Seriously, I grabbed my gear and left the area that night.
It's referred to as bioluminescence. Lots of fish light up, glow and have reflective qualities. The generation of light by living organisms is pretty interesting, so...google is your buddy here. Lots and lots of info on the web.
 
It's referred to as bioluminescence. Lots of fish light up, glow and have reflective qualities. The generation of light by living organisms is pretty interesting, so...google is your buddy here. Lots and lots of info on the web.

It is how Jim Lovell (Tom Hanks) explained finding his carrier when lost at night in Apollo 13.
 
I can't explain that...

And why in death does it fade?

I caught a dorado that looked like a jet propelled rainbow and when I pulled it out of the water the color just drained from it.:(

Hair, scales and feathers are analogous to each other in that the striations act as prisms to form the iridescent colors. That doesn't explain why people don't have iridescent hair though.:confused::confused::confused:
 
I'm hoping that Bear Bio or some fisheries biologist can tell me why piranhas and pacus shine with such an iridescent quality, in or out of water. They seem almost to sparkle.

Why? What quality in the scales produces this effect?

What's got me scratchin' my head... where is it that you go fishin' to see such fish? The've always been kinda rare here in Tennessee.
 
When you boat one of them fish... you use a net, don'tcha? Damn sure don't "lip" 'em... lessin' your name is Capt. Hook.

Just Googled up some pics of 'em... they look like bluegill sportin' a set of choppers that would do justice to a Great White.
 
What's got me scratchin' my head... where is it that you go fishin' to see such fish? The've always been kinda rare here in Tennessee.

A lot of people on this board are very egocentric.
Just because you don't see something in your neighborhood doesn't mean that it can't be interesting to others.

I think you can readily learn the range of various species of piranha/caribe even on Wikipedia. "Piranha" is used in Portuguese-speaking Brazil. It's usually "caribe" in Spanish-speaking countries.

I noticed the iridescence in aquariums, where I've seen a number of them, and even in photos. You can also probably see it on TV shows like that in which Jeremy Wade fishes South American rivers. BTW, he got a shock when he declared that the black piranha isn't dangerous, but found to his surprise that it is in some populations.

And Wade found that when the pacu was transplanted to New Guinea, they became carnivorous. Normally, they usually eat vegetation, one of the main differences between them and the true piranha. I don't live in New Guinea or in Brazil, but still find that of interest.

I think the poster who said that some scales and feathers act as prisms is on the right track.

It is true that colors of some fish do fade rapidly after death, as with the dolphin or rainbow trout. But that coloration isn't what I'm asking about.
 
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When you boat one of them fish... you use a net, don'tcha? Damn sure don't "lip" 'em... lessin' your name is Capt. Hook.

Just Googled up some pics of 'em... they look like bluegill sportin' a set of choppers that would do justice to a Great White.

And those choppers are so sharp and so interlocking that one man who was bitten by one said that he barely felt it before he realized that his finger was severely bitten and was bleeding badly. Larger ones can easily remove a finger in one bite.

Some think they're really small, but some individuals grow to over a foot long and are pretty wide.

If you have the chance, watch Jeremy Wade handle them...with great care. I think he uses pliers to remove hooks. His show, "River Monsters", recurs on Animal Planet, but you can find photos of him on the Net. He is not only an international angler, but is a biologist.

The worst bite that I ever got was from a walleye, and it hurt. I'm not going to put my hand close to the mouth of a pike, barracuda, or anything else with teeth that can really do some damage. BTW, walleye are a form of perch, not "walleyed pike" as some think.

Look up the African tiger fish. It looks like a striped bass with a mouth full of sharp bayonets. They're strongly suspected of having caused the disappearance of some fishermen who fell out of their canoes where schools of tiger fish were.

One of my favorites is the Payara. The lower jaw teeth are so long that with the mouth closed, the fangs protrude through the nostrils! This is the one that Wade calls the Vampire Fish on his show.
I've seen a number of mounted examples, and the sight is sobering. The long teeth are used to puncture the swim bladder on its victim fish.
 
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A lot of people on this board are very egocentric.
Just because you don't see something in your neighborhood doesn't mean that it can't be interesting to others.

Pardon me for livin', mister. I also found that there are maybe one or two... but not a lot... of condescendin', nose-in-the-air prima donnas on this board.

Those that I find agreeable and easy to deal with don't insinuate that others have writtin' words that never were scribbled... such as that we don't think "that it can't be interesting to others", either. While those one or two self-aggrandizin' folks try to make themselves appear lofty and intellectually superior... they sure put the rust on the blade for others with their lofty cacklin'.

So.. good day... mister high-falootin' Star. Please excuse me whilst I utilize the much needed in this case... "ignore" function.
 
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