Very interesting topic, too bad I dont't have the minutes, at the very moment, to review all the links above, but will asap.
Still, trying to give some input too, even if not read by myself yet.
I am also comparing the various patterns of the pores in the head, which are not the same on various botine loaches. Additional the shape and direction of the nares are finding my attention (what else?!

)) )
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lateral line
A sensory organ of fishes which consists of a canal running along the side of the body and communicating via sensory pores through scales to the exterior; functions in perceiving low frequency vibrations and pressure differences in general.
perhaps looking on sites like those, finds something
http://www.earthlife.net/fish/latline.html
this one has an English name, but appears German, they mean that some pores of the "lateral line" also appears on the head of fish. Nice diagramm though to look at like picture 3 ("Abb.3")
http://www.royal-flyfishing.com/cms/fro ... ?idcat=164
on cichlids, I saw a diagramm that pointed out about 8 different chanels on the head, which are connected to the channel of the lateral line.
THAT HERE SEEMS TO BE IT:
The laboratory fish
shoot, too much time spent again

but found another great link,
check this one out, shows very much detail, scroll down to see more excellent pictures.
Fish bioacoustics