Can Ram cichlid Live With Neon tetra?

This is the same idea as pairing the ram with a cardinal tetra, but with the wrong tetra. The ram needs warm water, 27 to 30 °C, and the neon tetra's own comfortable range tops out at 25, five degrees short. Keeping the ram warm enough stresses the neon; cooling the tank for the neon drops the ram out of the water it needs to stay healthy long term.

pH is not the problem: 4 to 7 covers both.

There is no tank size or feeding routine that closes a temperature gap this wide. If you want a tetra shoal for a German blue ram, the cardinal tetra tolerates the same warm water and is the tankmate its own profile actually recommends; keep neon tetras in a cooler community instead.