Hi narayana,
Before I could help you and give you some good answers to find out what is causing the neon tetras deaths, what are your water parameters? What is your pH, Ammonia, Nitrite, and Nitrate levels at? Your tank could still be cycling.
Could be adding 20 fishes at once to 90 litres, resulted in fishes dying back to what available bacterial colony could support.Thanks all for ur reply
@little soprano: i face the same situation here, bought 20 now left with 7, adding to this another 2 separated itself n dnt eat whenever i feed..
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