They can fit in a 20 gallon, but of your stocking list in your signature (1x Sunburst Wag Platy, 1x Hi Fin Platy, 1x Double Bar Platy, 1x Marigold Variatus Platy, 17x Neon Tetras, 2x Glass Catfish, 3x Oto Catfish, 1x Black Kuhli Loach, 2x Ghost Shrimp) All the platy's would need to go, it also may become uncomfortable for your black kuhli loach.Random reply but i wanted to know if a pair German Blue Rams can go in a 20 gallon tank
Unfortunately, german blue rams are very fragile and like the pH below 7, and temperature above 80. Platy's like a higher pH and low water temperature.
I also think your tank is well stocked as it is, or else I'd suggest bolivian rams which are easier to care for and accept the same water conditions.