We need pictures of the fish under normal light and with a dark substrate, a picture on the back of the tank, and some plants, so the fish feels secure. They won't show up any breeding colours in a bare bottom tank under blue light.
As a general rule with blue rams (German blue rams, or any other variety of blue ramirezi dwarf cichlid), the females get a pink patch on their belly when they are in breeding condition. Males get bigger and have longer fins than females, and males don't have a pink belly. The pink belly only shows up on mature females that are happy and in good condition.
If you want a breeding pair of rams (or any other cichlid), buy a group of 8-10 young fish and grow them up together. Let them pr off and remove the prs to their own tanks for breeding. If you just stick any two fish together, they might not get along and will fight or ignore each other. Sometimes putting two any fish together works but not always.
