Geographic Variant Morphology in S. rhombeus

[JoeDizzleMPLS]

wow....just wow.

So guys, what makes a Xingu a Xingu? What bout Guyana? What do you look for to id these types?

what makes a xingu a xingu is being collected out of the xingu river, what makes a guyana a guyana is being collected in guyana. it's cool to see all the pics of different rhoms, but its really hard to determine anything from pictures of rhoms that are in people's aquariums because most people just apply their own fancy names or they go by what the person who sold it to them called it, and most times, the fancy names were only applied so that they could charge more for a fish.

i think that this is an interestiing topic, but it can really only be discussed if we are using pictures of many fish that have just been taken out of the water where they were collected (like george's), because anything else is just a guess.

 

[Diogenes]

what makes a xingu a xingu is being collected out of the xingu river, what makes a guyana a guyana is being collected in guyana. it's cool to see all the pics of different rhoms, but its really hard to determine anything from pictures of rhoms that are in people's aquariums because most people just apply their own fancy names or they go by what the person who sold it to them called it, and most times, the fancy names were only applied so that they could charge more for a fish.

i think that this is an interestiing topic, but it can really only be discussed if we are using pictures of many fish that have just been taken out of the water where they were collected (like george's), because anything else is just a guess.

ok. well yeah I know that the names of CF rhoms come from the river or nation they were pulled out of, but are there not certain physical characteristics that you look for for each?

 

[JoeDizzleMPLS]

no, there really isnt. some fish do share the same characteristics, but just because a fish is collected from a certain area, it doesnt necessarily mean it will look like every other fish collected there.

it has gotten to the point now where every time someone sees a rhom with a humeral spot, everyone automatically assumes that it is a xingu, or every time someone sees a rather plain looking rhom, it is instantly just a boring old peru rhom, when someone sees a rhom with glittery scales, they call it a diamond rhom, and when someone sees a rhom with a bluish hue to it, they call it a blue diamond rhom.

it is cool to see the different looks that rhoms have, but you can't just look at the way the fish looks and automatically determine where it was collected... you could look at a fish and say "that looks alot like a picture i saw of a rhom that was collected near rio xingu" or "that rhom has a very steep dorsal region" and call it whatever you want, but you just can't know for sure where it was collected.

 

[dudey]

no, there really isnt. some fish do share the same characteristics, but just because a fish is collected from a certain area, it doesnt necessarily mean it will look like every other fish collected there.

it has gotten to the point now where every time someone sees a rhom with a humeral spot, everyone automatically assumes that it is a xingu, or every time someone sees a rather plain looking rhom, it is instantly just a boring old peru rhom, when someone sees a rhom with glittery scales, they call it a diamond rhom, and when someone sees a rhom with a bluish hue to it, they call it a blue diamond rhom.

it is cool to see the different looks that rhoms have, but you can't just look at the way the fish looks and automatically determine where it was collected... you could look at a fish and say "that looks alot like a picture i saw of a rhom that was collected near rio xingu" or "that rhom has a very steep dorsal region" and call it whatever you want, but you just can't know for sure where it was collected.

agreed, there really is no where to tell where a rhom was collected unless you pulled it out of that river.

There's no one that can just look at a picture of a rhom and determine where it is from. You cannot say that a rhom from this river will 100% have these distinct features.

Rhoms also change so much as they grow. A 2 inch rhom looks completely different from a 6 inch rhom, that looks different from a 9 inch rhom. A lot of their features that may be distinct to a certain river change as they grow and when they are put in the aquarium.

I know where my rhom was collected from (or I know at least where the collector said it was from), but when I posted it there was a couple people who were like nice peru rhom. good guess, but completely wrong like 95% of guesses. I really could care less where my fish was actually collected from. Really would not be a determining factor for me to purchase it. If I saw a peru rhom next to a rhom labeled as a Guayana rhom, if the peru one looked better I would grab him regardless of where he was from. The charecteristics of an individual fish should be a more determining factor then collection point.

A lot of times rhoms from different collection points catch more $ just because of how much different countrys allows to be exported each year.

As far as blue diamond, gd, black diamond, etc.. high back... just a way to describe a fish. Like blonde hair, red hair. Or blue accord, or red accord. You can really put any name on your fish.

 

[dudey]

http://www.monsterfishkeepers.com/forums/attachment.php?attachmentid=349156&stc=1&thumb=1&d=1239249513


If you would take each of those pictures and took away the names next to it, you would not be able to tell you which fish came from where with 100% certainty. Even if you had any resource available to you.



You may be able to say one is blue so blue diamond rhom but thats about extent of it.

But to say a fish from one river will have these distinct features is impossible.

 

[SharkAquarium]

I agree with you about 95%. Here is an example of an exception.

Notice the yellow on the gills? That says Xingu Rhom, at least to me.

 

[SharkAquarium]

And the marbling on this bad boy says Xingu Rhom (adult) to me. I have caught rhoms from at least a dozen places in South America, and this is the only example of this I have seen.

 

[SharkAquarium]

Here's another Xingu Marble Rhom. Note in the last 2 pics the more elongated body; shaped more like a black bass.

 

[SharkAquarium]

Here's another from the market.

 

[Diogenes]

no, there really isnt. some fish do share the same characteristics, but just because a fish is collected from a certain area, it doesnt necessarily mean it will look like every other fish collected there.

it has gotten to the point now where every time someone sees a rhom with a humeral spot, everyone automatically assumes that it is a xingu, or every time someone sees a rather plain looking rhom, it is instantly just a boring old peru rhom, when someone sees a rhom with glittery scales, they call it a diamond rhom, and when someone sees a rhom with a bluish hue to it, they call it a blue diamond rhom.

it is cool to see the different looks that rhoms have, but you can't just look at the way the fish looks and automatically determine where it was collected... you could look at a fish and say "that looks alot like a picture i saw of a rhom that was collected near rio xingu" or "that rhom has a very steep dorsal region" and call it whatever you want, but you just can't know for sure where it was collected.

Alright point taken. I understand that it is a somewhat futile effort to try and differentiate organisms beyond genus species binomial nomenclature. A scientist would think it's a waste of time, and only a hobbyist would be interested in color morphs of a given species, but being a hobbyist I think I would like to catalog those stereotypical traits that people normally associate with a CF rhom. I know that you can cast your rod and reel twice in the same place and get two completely different looking rhoms. I know that these stereotypes don't hold true 90% of the time, I'm not arguing that they do. I merely want to provide the information in an easy to follow format that people can figure out for themselves.

When people get into piranhas (rhoms) all they know is that they've got a piranha. After they figure out the difference between pygo and serra, they start to learn about the different "types" of rhoms. People on forums say, "hey that looks like a Xingu to me" and the new hobbyist is left wondering what the hell a xingu is. I read about piranhas all the time and I don't know what the hell a Xingu is (i mean I know it's a river), and I bet there are probably not that many people prepared to do the research to find out for themselves.

So if any of you guys that do know would like to share with the rest of us, we'd appreciate it.

Thanks everybody for all the great info. Thanks sharkaquarium for the great pics and info.

-C