Hi,
This is normal. The first specimen on the catelog is a small one if one considers the size of the head. The second one taken by Tiago is a breeding male. Males develop enlarged lips (like in
Hemiodontichthys, Loricariichthys, Pseudoloriaria, and Furcodontichthys)when brooding eggs. The third picture can be a female or a not breeding male. So that's why you are surprised by the difference. The size of plates can be more variable, but
Limatulichthys has well defined plates of medium size. Moreover the species is distributed all along the Amazon basin (and also in Orinoco). You can imagine that their is substantial variations between populations
![Wink ;-)](./images/smilies/icon/wink.gif)
.
Cheers
Raph.