Dwarf neon rainbowfish and rummies will never work. Giant danios are just about the options here as they are not fussy with the water conditions plus a bonus that they dwell the surface most of the time so harassments are minimal. Congo tetras on the other hand prefer soft acidic water at best so I won't recommend them either.tydus;1945345; said:Ok, for dithers, you guys think that the common rummy nose tetras can work? If not, I'll just switch back to getting dwarf neon rainbows for dithers.