Do I have bolivian Rams or German Blue Rams?

Pls help my other half was sold a "pair" of Bolivian Rams, but the more research I do the more I suspect we have been sold German blue Rams. The pair started off great but a few months down the line we are left with one. The larger one bullied the smaller one so much he died last week. I wanted to get another mate/s but I'm unsure of the what we actually have??
Here are some pictures.

 

GbR

 

Thanks

 

Yip its blue

 

Any ideas what the sex could be?

 

Thats a male German Blue Ram

 

I suspected it was, I was unsure as I have been told the methods I've used are not 100% and venting is the only sure way but I struggle to see ANY vent, think it could be due to him still been young??

 

My male and female

 

They look great, have you any advice on getting a new friend for him, sould I try getting one or two females? Or do they make pairs from been young or would he be best left on his own?

 

Its nice to have a pair i have 4 pairs of blue and one pair of Bolivians

 

I would love him to be part of a pair, would you advise getting just the one female or two and letting him pick?

 

One female because rams have only one partner get one female

 

Thanks again , I have search the Internet but this is the clearest answer I've had .