I wonder....

McEve · Post by **McEve** » Mon Jan 17, 2005 9:17 pm

What are the "nostrils" on plecos? Is it ears? Some kind of "antennas"? I've noticed that the Zebra's seem to respond to movement they can't possibly see, from both people and other fish. is this a sensory organ that pick up vibrations of some kind?

On this picture of a LDA33 you can see them very clearly, but they are also very pronounced on the Zebra's. I just don't have a picture that shows them as clearly as this one on the Zebra:

How's that for a bad mummy, I don't have any closeups of Zebras - so far!

Adam · Post by **Adam** » Tue Jan 18, 2005 12:25 pm

Hi McEve,

That's a cracking LDA33 you have there, nice picture too.

My extreme close ups tend to get out of focus, I suspect that you have a top end camera there. Is it a SLR by any chance?

The antenna type protrusions are actually nostrills but unlike mamalian nostrils they are not connected to the throat and are therefore not used for respiration. The nostrils are connected to an organ called the olfactory rosette which detects dissolved chemicals in the surrounding water. Fish such as sharks, salmon and eels have extremely well developed olfactory rosette organs that can detect chemical concentrations as low as 1 part per billion. This explains why eels and salmon are able to migrate thousands of miles back to the exact river they were spawned in and why sharks are such efficient predators. Sharks and Rays also possess an additional set of pit like nostrils that they use to sense electrical potential(voltage). These sensors are so sensitive that if there were not any other distortions a shark could detect the heartbeat of a fish 500 miles away

Fish are able to sense vibrations in water through the use of their inner ears and the lateral line organ, I'll save that explanation for another day.

McEve · Post by **McEve** » Tue Jan 18, 2005 12:49 pm

Thanks Adam, he is a beaut isn't he

It's actually not a closeup, it's a crop from this one (which also is a crop...):

The camera is a Nikon coolpix 8800.

Thanks for the explanation about the nostrils! When you mention it I seem to remember having read somewhere that they have sensory organs along a line of the body that pick up vibrations?

Sure is interesting creatures we keep

hamish99 · Post by **hamish99** » Wed Jan 19, 2005 12:14 am

how big do LDA33 get to?

McEve · Post by **McEve** » Wed Jan 19, 2005 12:42 am

I've seen them at 20cm. I believe this is the max size, but I do not know for sure