Sexing Lamontichthys Llanero

[parrot1974]

Hi all
I have a pair of these lovely fish that I bought from two different sources. They are eating well and I am hoping that they might eventually breed. Neither of them has any obvious odontodes anywhere, but I was hoping that it might be able to sex them as they are both adult size.
I've read some of the posts on this forum about using odontodes or the shape of the head or even their scutes. Their head do seem to be a slightly different shape, they have no obvious odontodes and I can't find any information on exactly how their scutes differ.
However, their dorsal fins are very different and I wondered whether this was sex-related. I have attached photos of both fins. One is a lower angle, with longer filaments (and this one also has slightly longer filaments on its other fins), whereas the second one holds its fin at a higher angles and has more of a hook to it.
Can anyone help with this please, or even let me know any further differences with regard to their scutes?
Thanks