# Fish measuring



## Sir Nathan XXI (Jan 29, 2003)

here is the picture Frank made via his estimation method which I would like him to explain how it is done.










I also figured out why large and fat fish pics make them look smaller just now, their girth makes the body arch when layed on a flat surface. I have a 10" net and I pinned her to the glass getting her out and she hung out of the net quite a bit and its a 10" net, you can tell she is arched in the picture, she was flopping like crazy and nearly bit my hand while I was moving the tape so this is the best pic I could get









my guess is she is actually 10.75" TL the 11.25"TL before was made through the water so it made her look bigger.

her is her laying on side









Franks method appears to be well within 10% so its pretty accurate, how do you do it?


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## 521 1N5 (Apr 25, 2003)

THAT'S A DAMN FAKE!!

J/K nate!


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## Sir Nathan XXI (Jan 29, 2003)

goldfish chunks in teeth said:


> THAT'S A DAMN FAKE!!
> 
> J/K nate!


 I was gonna say nearly got bit over this, its as real as it gets


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## Xenon (Nov 15, 2002)

He knows the measurment of the eye and uses it to scale. piranha eyes have fixed size when they get to a certain age. correct me if i am wrong frank.


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## Xenon (Nov 15, 2002)

Xenon said:


> He knows the measurment of the eye and uses it to scale. piranha eyes have fixed size when they get to a certain age. correct me if i am wrong frank.


 If you straighten out the ruler, I bet frank is much closer than you are giving him credit for.


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## hastatus (Jan 16, 2003)

> Xenon Posted on May 12 2003, 11:40 PM ...If you straighten out the ruler, I bet frank is much closer than you are giving him credit for.


Mike you are taking the fun out of this.











> Xenon Posted on May 12 2003, 11:38 PM
> --------------------------------------------------------------------------------
> He knows the measurment of the eye and uses it to scale. piranha eyes have fixed size when they get to a certain age. correct me if i am wrong frank.


 Exactly right on. Which is why the ex-knifeman bubba fish is next on the agenda. I have another person working on it and he should get credit for those measurements using the methods described.

It won't really matter one way or the other on that fish, without it being on a tape measurement. Even so, approximations work well to.

Nate, thank you for you honest post.


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## RedShoal (May 3, 2003)

The image of Super's photo that I used photo shop to rotate the ruler straight and just moved straight up. The fish is 10" in size when you do that.

BTW, how do I post an image?


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## hastatus (Jan 16, 2003)

Here you all can play with the measurements:


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## Xenon (Nov 15, 2002)

With the ruler straightened using photoshop, I swear on pfury i lined the pixels perfect using the 6 of your own ruler as measurement. It comes out to ~ 9.25" SL....eyeball estimate for TL is like 9.5 or so....

_the black spots are where i tried to make the divisions of the inches appear more visible. too lazy to pretty the image up. _


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## hastatus (Jan 16, 2003)

Above you ADD and PREVIEW POST is a BROWSE Box to access photos on My Computer.


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## 521 1N5 (Apr 25, 2003)

not good w/measurments but that's a hell of a nice looking fish man!


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## RedShoal (May 3, 2003)

Don't be a joy kill, if the fish was bigger, then the angle will matter.

The difference as according to angle versus the centered line is [A/cos(x)]-A = Error
A is the length of the adj. line to the hyp. line. X is the angle between the two.

Its a small fish and a 20% difference will only produce .64" difference.


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## Xenon (Nov 15, 2002)

RedShoal said:


> Don't be a joy kill, if the fish was bigger, then the angle will matter.
> 
> The difference as according to angle versus the centered line is [A/cos(x)]-A = Error
> A is the length of the adj. line to the hyp. line. X is the angle between the two.
> ...


 Who are you referring to?


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## InSinUAsian (Jan 3, 2003)

That sure does suck. Makes measuring fish totally different. Now that I look at it, my altuvei may be a little smaller then previously thought. [email protected] formalities. Blah!

~Dj


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## RedShoal (May 3, 2003)

hastatus said:


> Above you ADD and PREVIEW POST is a BROWSE Box to access photos on My Computer.





hastatus said:


> Above you ADD and PREVIEW POST is a BROWSE Box to access photos on My Computer.


Thanks.









But I get this.

THE FOLLOWING ERROR(S) WERE FOUND
--------------------------------------------------------------------------------
You cannot upload this type of file


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## RedShoal (May 3, 2003)

Xenon said:


> RedShoal said:
> 
> 
> > Don't be a joy kill, if the fish was bigger, then the angle will matter.
> ...


 Oops, I mean 20 degree difference.

I was referring to Frank's pic of that fish with the yellow line that went straight down to the 10" mark on the ruler. And I was using math here on paper and photoshop... when I could have done the same thing. Silly me.


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## hastatus (Jan 16, 2003)

> THE FOLLOWING ERROR(S) WERE FOUND
> --------------------------------------------------------------------------------
> You cannot upload this type of file


Down size your photo to many pixels.


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## Xenon (Nov 15, 2002)

To alleviate any confusion, I have withdrawn the last inch of the ruler to expose where the line of pixels extends....right under the nose....perfectly.


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## hastatus (Jan 16, 2003)

Keep in mind there are 3 lines there, TL (TAIL) SL (hypural plate) and snout (10 inch mark).


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## Xenon (Nov 15, 2002)

I would usually not get into this but its so damn fun to play with photoshop.


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## Xenon (Nov 15, 2002)

hastatus said:


> Keep in mind there are 3 lines there, TL (TAIL) SL (hypural plate) and snout (10 inch mark).


SL is not close to 10 inches. Damn impressive fish though! Look at its colors!


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## RedShoal (May 3, 2003)

My question here is what is going on here? Are we trying to verify a record?


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## Xenon (Nov 15, 2002)

RedShoal said:


> My question here is what is going on here? Are we trying to verify a record?


 See ^^^^^ post. Having fun with photoshop and verifying Franks method of "forensic" picture measuring. So far, pretty damn dead on.


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## Sir Nathan XXI (Jan 29, 2003)

yeah we are just trying to find the methods accuracy, its pretty darn close with sq pics of the fish


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## hastatus (Jan 16, 2003)

> Xenon Posted on May 13 2003, 12:00 AM ...SL is not close to 10 inches.


 Which is why I used TL; 10 inches + or - on the untape measured fish. Remember 50 mm (2 inches) is generally added to the tail to make up the TL from SL.


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## InSinUAsian (Jan 3, 2003)

Xenon said:


> See ^^^^^ post. Having fun with photoshop and verifying Franks method of "forensic" picture measuring. So far, pretty damn dead on.


This is a very valid method of measuring items in pictures. As long as you have a reference to base it against. I did some work as and undergrad lab assistant where I did photoshop measurements, similar to this day in and day out. I believe the correct term for it is "pelemetry" (sp?). Well based on the measurements we took similar to this, we published our work and proved our theories. And this was all work done for the UCSF. Very serious stuff.

~Dj


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## Xenon (Nov 15, 2002)

hastatus said:


> > Xenon Posted on May 13 2003, 12:00 AM ...SL is not close to 10 inches.
> 
> 
> Which is why I used TL; 10 inches + or - on the untape measured fish. Remember 50 mm (2 inches) is generally added to the tail to make up the TL from SL.










I was actually one pixel off on the second to last inch...oh well, its close enough.


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## RedShoal (May 3, 2003)

I see your measured fish and I raise you a flying bug eyed P.


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## hastatus (Jan 16, 2003)

Hey you loaded it up ! Congrats.


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## RedShoal (May 3, 2003)

hastatus said:


> Hey you loaded it up ! Congrats.


 Thanks for your help, you were correct about the size. :smile:


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## hastatus (Jan 16, 2003)

> Xenon Posted on May 13 2003, 12:02 AM
> --------------------------------------------------------------------------------
> QUOTE (RedShoal @ May 12 2003, 07:01 PM)
> My question here is what is going on here? Are we trying to verify a record?
> ...


Really?


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## Sir Nathan XXI (Jan 29, 2003)

so Frank what is the eye size you use then on adults? in mm is fine?


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## hastatus (Jan 16, 2003)

> InSinUAsian Posted on May 13 2003, 12:08 AM
> --------------------------------------------------------------------------------
> QUOTE (Xenon @ May 12 2003, 05:02 PM)
> See ^^^^^ post. Having fun with photoshop and verifying Franks method of "forensic" picture measuring. So far, pretty damn dead on.
> ...


The reference point Dj is the eye diameter which is 7.9 mm fixed on adult piranas which I actually increased for photo usage to a full 1/2 inch. So its actually larger than life but gives the approximation desired.


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## hastatus (Jan 16, 2003)

But then what do I know about forensics with all these dead piranas laying around.


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## Sir Nathan XXI (Jan 29, 2003)

what size piranhas have the standard size eye, like min size till they have that eye size, and dont you mean radius of 7.9mm, a diameter of 7.9mm = .252 inches


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## RedShoal (May 3, 2003)

This is werid I get .311023622047" for 7.9 mm


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## Grosse Gurke (Jan 3, 2003)

Nice cariba Nate. From looking at the pic, it looks like 10" TL. You said he was bending and that could be where he looses some of his size. Very nice fish reguardless of size. From now on, I am going to subtract 2" from my fish just to be on the safe side!!







:smile:


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## hastatus (Jan 16, 2003)

As I told you in the PM, the iris is measured at 7.9 mm or a bit under a 1/4 inch. Adding the orbit is approx. 10 mm. or a bit under 1/2 in.



> Frank here are the photos of my Cariba acurately measured at just over 11"TL from the upper lip, I would like to see how accurate your method is, feel free to edit the pics with your measurement markings, I would like to see how you do it so we can figure out how accurate it is


I thought you said you measured this fish at over 11 inches? Your ruler doesn't show that.



> Xenon Posted: May 12 2003, 10:03 PM
> 
> QUOTE (Sir Nathan XXI @ May 12 2003, 04:51 PM)
> I saw Bubba (johns old fish), and I have measure my largest cariba acurately at just over 11" TL
> ...


I guess this puts old Bubba back in the _Oh Yeah? _ eh?


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## hastatus (Jan 16, 2003)

Good grief.....he has me making mistakes now.


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## hastatus (Jan 16, 2003)

> hastatus Posted on May 13 2003, 12:34 AM
> --------------------------------------------------------------------------------
> As I told you in the PM, the iris is measured at 7.9 mm or a bit _under_*OVER* a 1/4 inch. Adding the orbit is approx. 10 mm. or a bit under 1/2 in.
> 
> ...


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## RedShoal (May 3, 2003)

Good grief!

Sometimes these threads just go into the twilight zone.


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## hastatus (Jan 16, 2003)

> RedShoal Posted on May 13 2003, 12:37 AM
> --------------------------------------------------------------------------------
> Good grief!
> 
> Sometimes these threads just go into the twilight zone.


Tell me about it. I'm getting dinner. You all have fun.


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## hastatus (Jan 16, 2003)

b4 I forget here are the eye diameter measurements for the 3 pygocentrus;

nattereri: 7.9 mm; cariba: 8.7 mm and piraya: 8.4 mm add plus 2mm for the orbit.

Later~


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## Sir Nathan XXI (Jan 29, 2003)

my initial measurement was the fish in a tupperware bin when I got it. I put the tape measure down into the water, so the fish wasnt arched over at all and water does magnify some but it was just 11 give or take a 1/4" but from the pic it doesnt look that way, I guess the only way to get perfect measurements is to sit the fish on its belly standing up with calipers snout to tail or tail base for SL

laying on side has its errors


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## Grosse Gurke (Jan 3, 2003)

Well, I have a hard time seeing that fish at 11", even fully streched out. And I could be mistaken, but I thought you initally said he was 12".


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## Sir Nathan XXI (Jan 29, 2003)

nah never said she was much over 11"


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## Grosse Gurke (Jan 3, 2003)

Thats cool, I could not remember with all these mamoth fish being reported. :smile:


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## Sir Nathan XXI (Jan 29, 2003)

grosse gurke said:


> Thats cool, I could not remember with all these mamoth fish being reported. :smile:


 Wes PK has bigger Cariba than I do, thats who you are thinkin of


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## hastatus (Jan 16, 2003)

> QUOTE
> Frank here are the photos of my Cariba *acurately measured at just over 11"TL* from the upper lip,





> Sir Nathan XXI Posted on May 13 2003, 01:42 AM
> --------------------------------------------------------------------------------
> nah never said she was much over 11"


If I'd only be paid a 1$ each time Nate played with words.







Going to Arby's see you all later. Perhaps Nate will provide us with more entertainment.


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## Sir Nathan XXI (Jan 29, 2003)

hastatus said:


> > QUOTE
> > Frank here are the photos of my Cariba *acurately measured at just over 11"TL* from the upper lip,
> 
> 
> ...


 is it just me or do both of these quotes say the same thing


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## hastatus (Jan 16, 2003)

> Sir Nathan XXI Posted on May 13 2003, 02:37 AM ......*is it just me* or do both of these quotes say the same thing





> my initial measurement was the fish in a tupperware bin when I got it. *I put the tape measure down into the water, so the fish wasnt arched over at all and water does magnify some but it was just 11 give or take a 1/4"* but from the pic it doesnt look that way, I guess the only way to get perfect measurements is to sit the fish on its belly standing up with calipers snout to tail or tail base for SL


It's you.......that's a far cry from _accurate!_


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## Sir Nathan XXI (Jan 29, 2003)

and I already said that


> my guess is she is actually 10.75" TL the 11.25"TL before was made through the water so it made her look bigger.


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## Xenon (Nov 15, 2002)

This topic is done.


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