neons are not the best tankmates for discus as they don't do very well in temperatures of 28-29, they prefer 24-25. Other tetras that would be better suited include Cardinal tetras or rummynosed tetras... some people find glowlight tetras or Bleeding heart tetras good also and they are alot cheaper than rummynoses or cardinals. Other good fish are clown loaches, corys, SAE's, dwarf pencilfish, Rams, fancy plecs, etc...
hope that helps