Can Someone Identify These Fish Please?

I just got back from my LFS, after searching around for some peacock gobies. The bigger, chunkier one of these two was in a tank with some black widow tetras, and after talking about him I was told it was a peacock goby. I asked if there were any more for sale and in the tank next to it there was the smaller, more darker patterned one. Which I have absolutely no idea of species or sex.
 
To me they look like Garras or Gobies, but which type I have no clue.
 



 
Hope someone can shed some light on these fish, as they're gorgeous looking and I really want to give them optimum conditions.

Does anyone know? so confused as they could be anything!

Its a species of Stiphodon goby the black stripey one is female and the plain coloured one is an uncoloured male.

Ah, not what I was completely expecting then. Bit worried as this species is said to live in flowing rivers? I don't know how reliable the information i've come up with is, but apparently they go to 4-5cm, the male's easily 6cm already. In a bit of a state of turmoil here, as there's not even much algae growth in my tank for them to regularly graze on... The male's dug a hole in the sand under my bog wood and is completely out of sight, don't know where the female is..

In my experience they do just great on frozen foods and live foods and eventually seem to move on to flakes or pellets too
 
I also think that males caneasily achieve 6cm, i wouldnt expect him to get bigger though..

Thanks a lot
 
Fed today and they took some bloodworms, as well as stealing a bit of the algae wafer haha, they are amazing little characters! I'm going to upload a video of them!!