Originally Posted by db8
i see. how about cardinal tetras with the neon tetras?
Yes, at one time I did add cardinal tetras and they mixed in well with the neon tetras - the two even schoaled together. But eventually the cardinal tetras did not last because my water pH was not low enough. At that time, my plants were growing so well that the day time pH peaked as 7.8. The cardinal tetras just couldn't take such high pH.
Right now, I am experimenting with pressurized CO2 to lower the water pH. The neon tetras like that - they are more active and have better appetite. May be one day I will re-introduce cardinal tetras.