# Does anybody have any more information on S. marginatus?



## diogenes (Nov 11, 2008)

So I believe I have conclusively identified my fish as an S. marginatus. It was sold to me as such, and now that its coloring up it's clearly showing all he hallmarks of a marginatus. Let me take this opportunity to thank the people behind OPEFE. OPEFE is an amazing resource and we piranha keepers would be lost without it. So I have googled marginatus and read everything I can find, but I still feel like there is something missing from the information I have gathered. Other hobbyist can tell you about the overall nature and behavior of a Rhom or an RBP, and they can tell you their growth rates, aggression levels, and behavior, but not for a marginatus.

Can anybody tell me what the over all behavior/character is of this fish? How fast do they grow? Can anybody point me towards any good info besides OPEFE?

Thanks,
-C


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## white_blue_grey (Jan 23, 2009)

Do u have a picture of your fish? I would love to see, lol~~
I don't know if you have see this website yet, but it give you pretty much everything you need to know about piranhas~~
http://www.piranha-info.com/default.php?la...&id=sitelog


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## Grosse Gurke (Jan 3, 2003)

When you are talking about solo Serrasalmus in the aquarium....I have not really noticed characteristic that would be attributed to the species of the fish...and not the individual fish. You can take 3 rhoms and put them in identical tanks....and they will all behave a little different. In the aquarium...and with a solo fish.....I think the Genus Serrasalmus is more a representative of the fish's behavior...then the species. If you want to talk about groups of fish....that is something entirely different. I kept a small group of marginatus together for about 6 or 8 months...and they act very much like irritans in a group.

So basically.......your fish in general...wont act much different then a rhombeus or maculatus....however it will have its own set of individual traits.


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## diogenes (Nov 11, 2008)

white_blue_grey said:


> Do u have a picture of your fish? I would love to see, lol~~
> I don't know if you have see this website yet, but it give you pretty much everything you need to know about piranhas~~
> http://www.piranha-info.com/default.php?la...&id=sitelog


Yeah I have a few decent pics available on this thread:

http://www.monsterfishkeepers.com/forums/s...ad.php?t=204327

and no I hadn't seen that site, but unfortunately there's not much info on the species marginatus there... Thanks anyway...


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## Piranha Guru (Nov 24, 2005)

diogenes said:


> So I believe I have conclusively identified my fish as an S. marginatus. It was sold to me as such, and now that its coloring up it's clearly showing all he hallmarks of a marginatus. Let me take this opportunity to thank the people behind OPEFE. OPEFE is an amazing resource and we piranha keepers would be lost without it. So I have googled marginatus and read everything I can find, but I still feel like there is something missing from the information I have gathered. Other hobbyist can tell you about the overall nature and behavior of a Rhom or an RBP, and they can tell you their growth rates, aggression levels, and behavior, but not for a marginatus.
> 
> Can anybody tell me what the over all behavior/character is of this fish? How fast do they grow? Can anybody point me towards any good info besides OPEFE?
> 
> ...


My marginatus seems to be the meanest of all my serras. I got him from Ex0dus who had a failed cohab because they were "the meanest 2" of fish" he'd ever seen. I've had it for a couple of years and it has gone from under 2" to over 5".

I'd like to see a good lateral shot of your fish without flash. I'm not convinced by the pictures you linked to the other forum that your fish is a marginatus. Post up a thread in the ID forum.


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## Gigante Pirana (Apr 23, 2004)

If you have access to an College or University library, try the 2 sources:

1. "Underwater observation of piranhas in Western Brazil", found in the journal= Environmental Biology of Fishes, Vol 28, numbers 1-4/August 1990, pages 17-31.

2. "Patterns of food resource use by two congeneric species of piranhas..." , found in Braz J Biol. 2003 May, 63(2) 177-82.

Excellent reads on the fact s.marginatus are solitary, highly aggressive piranha species in the wild, especially when confronted with s.spilopleura species.

There are more but I don't remember at the moment their references. Good luck with these 2.


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## Piranha Guru (Nov 24, 2005)

Gigante Pirana said:


> If you have access to an College or University library, try the 2 sources:
> 
> 1. "Underwater observation of piranhas in Western Brazil", found in the journal= Environmental Biology of Fishes, Vol 28, numbers 1-4/August 1990, pages 17-31.
> 
> ...


I'm pretty sure you have forgotten more than I will ever learn about piranhas... I was able to google those two article titles and found them pretty quickly.


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## diogenes (Nov 11, 2008)

BioTeAcH said:


> So I believe I have conclusively identified my fish as an S. marginatus. It was sold to me as such, and now that its coloring up it's clearly showing all he hallmarks of a marginatus. Let me take this opportunity to thank the people behind OPEFE. OPEFE is an amazing resource and we piranha keepers would be lost without it. So I have googled marginatus and read everything I can find, but I still feel like there is something missing from the information I have gathered. Other hobbyist can tell you about the overall nature and behavior of a Rhom or an RBP, and they can tell you their growth rates, aggression levels, and behavior, but not for a marginatus.
> 
> Can anybody tell me what the over all behavior/character is of this fish? How fast do they grow? Can anybody point me towards any good info besides OPEFE?
> 
> ...


My marginatus seems to be the meanest of all my serras. I got him from Ex0dus who had a failed cohab because they were "the meanest 2" of fish" he'd ever seen. I've had it for a couple of years and it has gone from under 2" to over 5".

I'd like to see a good lateral shot of your fish without flash. I'm not convinced by the pictures you linked to the other forum that your fish is a marginatus. Post up a thread in the ID forum.
[/quote]

It's a marginatus. Why is it that people doubt it's a marginatus? Name another serra with an orange adipose fin, and an orange anal fin with black border proximal to the body. Yeah...there's not one..... Thanks anyway...

compare:

Darwin- my fish










S. Marginatus from OPEFE










Clearly these are the same species. If your "marginatus" doesn't look like mine, then it's not a marginatus. Maybe you should post a pic in the ID section.


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## Piranha Guru (Nov 24, 2005)

diogenes said:


> It's a marginatus. Why is it that people doubt it's a marginatus? Name another serra with an orange adipose fin, and an orange anal fin with black border proximal to the body. Yeah...there's not one..... Thanks anyway...
> 
> compare the pics in that link I posted to this pic from OPEFE:
> 
> http://www.angelfire.com/biz/piranha038/im...ictures_040.jpg


If you mean ones similar in coloration to your pictures, then how about sanchezi, compressus, and juvenile rhoms...several serras fit that description at one time or another during development.

The key to IDing marginatus is the extremely convex forehead with sharply pointed snout, laterally compressed body, the thick proximal band on the caudal fin that almost reaches the dorsal and ventral tips, and that ever-so-conspicuous hook shaped anal fin due to the elongated anterior ray(s) of the anal fin. Coloration varies from yellow to orange to red. Collection point can be helpful too.

You may want to take a closer look at those pictures of marginatus at OPEFE and put them side by side to your fish, then do the same thing with sanchezi and compressus. People doubt it is a marginatus because it does not posses the tell tale features of a marginatus...you don't have to agree with me, but post a good lateral shot in the ID forum and see what other experienced serra keepers think.


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## diogenes (Nov 11, 2008)

BioTeAcH said:


> It's a marginatus. Why is it that people doubt it's a marginatus? Name another serra with an orange adipose fin, and an orange anal fin with black border proximal to the body. Yeah...there's not one..... Thanks anyway...
> 
> compare the pics in that link I posted to this pic from OPEFE:
> 
> http://www.angelfire.com/biz/piranha038/im...ictures_040.jpg


If you mean ones similar in coloration to your pictures, then how about sanchezi, compressus, and juvenile rhoms...several serras fit that description at one time or another during development.

The key to IDing marginatus is the extremely convex forehead with sharply pointed snout, laterally compressed body, the thick proximal band on the caudal fin that almost reaches the dorsal and ventral tips, and that ever-so-conspicuous hook shaped anal fin due to the elongated anterior ray(s) of the anal fin. Coloration varies from yellow to orange to red. Collection point can be helpful too.

You may want to take a closer look at those pictures of marginatus at OPEFE and put them side by side to your fish, then do the same thing with sanchezi and compressus. People doubt it is a marginatus because it does not posses the tell tale features of a marginatus...you don't have to agree with me, but post a good lateral shot in the ID forum and see what other experienced serra keepers think.
[/quote]

Compressus looks similiar, as do most of the compressus group of serras, but my guys head is shaped more like a marginatus and less like a compressus. Sanchezi not so much. The proportions are all wrong, and the adipose fin is a different color. The elongated rays on the anal fin come with maturity, and good fish keeping. My guys still pretty young and I've only had him for a couple months. When I got him, his colors were all washed out, and his fins were frayed. I added aquarium salt and the fins healed, but they haven't had time to grow a hook. I bought him as a marginatus, posted photos of him on here and on MFK, and got a dozen different ID's. It wasn't until I met some people that knew what they were talking about they I could make a good ID on him. I'm really not interested in hearing more uninformed conjecture about his species. OPEFE was a huge help. Look at those pics. The fish are identical.


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## Piranha Guru (Nov 24, 2005)

diogenes said:


> compare:
> 
> Darwin- my fish
> 
> ...


My marg 2 years ago:









Same marg in December:


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## diogenes (Nov 11, 2008)

BioTeAcH said:


> compare:
> 
> Darwin- my fish
> 
> ...


My marg 2 years ago:

View attachment 178094


Same marg in December:

View attachment 178095

[/quote]

well I'm sure just like with all the other species of piranhas both serra and pygo, there's some regional variation in color morph. You marg looks a lot like the pictures depicting a different morph on the site.


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## Piranha Guru (Nov 24, 2005)

diogenes said:


> Compressus looks similiar, as do most of the compressus group of serras, but my guys head is shaped more like a marginatus and less like a compressus. Sanchezi not so much. The proportions are all wrong, and the adipose fin is a different color. The elongated rays on the anal fin come with maturity, and good fish keeping. My guys still pretty young and I've only had him for a couple months. When I got him, his colors were all washed out, and his fins were frayed. I added aquarium salt and the fins healed, but they haven't had time to grow a hook. I bought him as a marginatus, posted photos of him on here and on MFK, and got a dozen different ID's. It wasn't until I met some people that knew what they were talking about they I could make a good ID on him. I'm really not interested in hearing more uninformed conjecture about his species. OPEFE was a huge help. Look at those pics. The fish are identical.


Your fish's head and snout is much more blunt than a marginatus.

Check out the pics of juvi margs on OPEFE...they have the tail hook...mine has had it since 2-3".

Your fish is not that young.

Until you open your mind to the fact that your fish may not be a marginatus, you will never see what is before your eyes. Your fish and OPEFE's fish pictured are nowhere close to being identical.

OPEFE Compressus photo compared to one of your other photos under similar lighting conditions:

















I'm not saying your fish is 100% compressus, but it has more of a shot at that than marginatus. Remember that color is always the last thing you should look at...focus on the fins (dorsal, caudal), body shape, spotting, and collection point.


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## Grosse Gurke (Jan 3, 2003)

Sorry...but the fish doesnt look like S. marginatus to me. Believe what you want....but Darwin doesnt look anything like the fish from OPEFE.


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## Lifer374 (Dec 5, 2003)

I agree.

Its not a marginatus. Its a compressus. And a nice one.


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## diogenes (Nov 11, 2008)

look guys I appreciate the help really, and I'm not married to the idea of it being a marginatus. Honestly I don't really care if what species name it is, but I am sitting in my living room looking in the tank, and I trust my fish dealer. Could there have been some mistake in identifying him? Sure but people on the internet aren't going to catch it from a few low quality pics I posted. To me the two pics I posted side by side look exactly the same minus the anal fin extensions. My fish is the same species as that fish, whether or not that is a marginatus I don't know, but thats what my fish looks like.


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## diogenes (Nov 11, 2008)

BioTeAcH said:


> Compressus looks similiar, as do most of the compressus group of serras, but my guys head is shaped more like a marginatus and less like a compressus. Sanchezi not so much. The proportions are all wrong, and the adipose fin is a different color. The elongated rays on the anal fin come with maturity, and good fish keeping. My guys still pretty young and I've only had him for a couple months. When I got him, his colors were all washed out, and his fins were frayed. I added aquarium salt and the fins healed, but they haven't had time to grow a hook. I bought him as a marginatus, posted photos of him on here and on MFK, and got a dozen different ID's. It wasn't until I met some people that knew what they were talking about they I could make a good ID on him. I'm really not interested in hearing more uninformed conjecture about his species. OPEFE was a huge help. Look at those pics. The fish are identical.


Your fish's head and snout is much more blunt than a marginatus.

Check out the pics of juvi margs on OPEFE...they have the tail hook...mine has had it since 2-3".

Your fish is not that young.

Until you open your mind to the fact that your fish may not be a marginatus, you will never see what is before your eyes. Your fish and OPEFE's fish pictured are nowhere close to being identical.

OPEFE Compressus photo compared to one of your other photos under similar lighting conditions:

View attachment 178097


View attachment 178098


I'm not saying your fish is 100% compressus, but it has more of a shot at that than marginatus. Remember that color is always the last thing you should look at...focus on the fins (dorsal, caudal), body shape, spotting, and collection point.
[/quote]

the fins on that compressus are the wrong color.


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## Piranha Guru (Nov 24, 2005)

diogenes said:


> look guys I appreciate the help really, and I'm not married to the idea of it being a marginatus. Honestly I don't really care if what species name it is, but I am sitting in my living room looking in the tank, and I trust my fish dealer. Could there have been some mistake in identifying him? Sure but people on the internet aren't going to catch it from a few low quality pics I posted. To me the two pics I posted side by side look exactly the same minus the anal fin extensions. My fish is the same species as that fish, whether or not that is a marginatus I don't know, but thats what my fish looks like.


Suite yourself...we're just trying to help you figure out what it is you actually have. Going around posting pics as a marginatus when it is obviously not just adds to the confusion of those not familiar with all the species of serras. Those pics are more than adequate to see the differences in dorsal fin, anal fin, tail fin, and body shape...your fish is not the same species. You are comparing a fish around 5" which would make it a subadult comp, sanch, or juvenile rhom to a fully grown, thick, adult 10" marginatus. You should be looking at pictures of marg of around 5" and the differences become even more obvious. Dealers screw up all the time on juvenile serras. How big was it when you got it? What is the collection point? What was its condition? An emaciated comp, sanch, or rhom can appear to share the same body shape as a marg because they are so skinny and the fat hump is depeleted giving the forehead a sharper look.

Anyhow, it is a great looking fish regardless and Darwin is a great name. We don't have to agree on ID to see that! Let what we have said marinate for a while and post up a good side shot without flash in the ID section when you have a pic that you feel does Darwin justice.


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## Piranha Guru (Nov 24, 2005)

diogenes said:


> the fins on that compressus are the wrong color.


You need to get over the whole color thing...color is too variable due to collection point, diet, stress, disease, and even lighting, substrate, and decor in a photo to be used as a reliable ID factor. Focus on the things that matter most, body shape/proportions (forehead, mouth, length vs height, etc..), fin shape and markings, eyes, and visible spotting patterns. They are less variable and much more reliable. Frank at OPEFE will tell you that color is the last thing he will look at.


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## diogenes (Nov 11, 2008)

alright alright you've made some reasonable points, and the only thing I know for sure is that I don't know everything. I'm going to use some of the same pics I have already taken because he hides under that mangrove thing and it makes it hard to take good lateral pics without taking the whole tank apart. I sincerely do appreciate some well informed opinions, and the last thing I would want to do is mislead people by posting erroneous information. Thanks on the compliments. Whatever he is he's a pretty fish, and I certainly am enjoying him. Given the difficulty I've had with taxonomy and this fish, Darwin may be the a more apropos name that I thought when I gave it to him. Maybe I should just call him "Serrasalmus sp. Darwin" hehe....

I hope some of you guys know what your talking about because the last time I did this, I heard everything from Rhom to RBP. I'm relatively certain he's in the compressus group. That means possibly a compressus, marginatus, or altuvei. Also, if we identify him as a something else, and he grows a hook on his anal fins we're gonna be brawlin! Thanks again guys hopefully we can identify him once and for all.


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