[FrogEyes]

Plants can help your water quality, but Pachytriton live in environments with almost NO plants.


There are presently seven known species, one still unnamed.

You're right that your pictures aren't detailed enough to identify the species. Even with better pictures it can be very difficult if not impossible to be sure. However, I would already be willing to say...
Not labiatus. Labiatus isn't a Pachytriton. (It's a Paramesotriton, and the familiar pachys were renamed inexpectatus)
Not inexpectatus. P.inexpectatus is solid brown above.
Not moi. P.moi is solid brown above and lacks red when mature.
Not archospotus. P.archospotus has a different build and lacks dorsal red marks.

The rest...
Probably not brevipes, due to presence of red coloring.
Probably not feii, which is thus far only known to be unspotted brown above.
Could be the undescribed species related to brevipes, but nothing has been described of this species.
Probably P.granulosus, which is normally slender and dark brown above with red dorsolateral spots or stripes. However, some populations are spotted and some are spotted and also have red marks. I'll have to check the literature [AGAIN] to see if ALL the brevipes-like populations were assigned to granulosus, or if brevipes still includes some 'odd' populations.