It sounds like you somehow crashed the bacteria colony. Best bet is to find some established filter media to kick start again. Or i have found thr probidio product (biodigest + biotrace) are very useful for jump start.
Suggestion on mid-dweller softwater fish that can tolerate "decent" flow?
Hi all, it's been a while
So finally i've set up my 170x50x60 tank with fast moving - blackwater style.
The tank has a huge piece of wood and thick sand bottom with plants mainly attached to the wood. Flow rate is something like 2500-3000l/hr
The tank is meant for some pleco but Im not adding any pleco yet until the tank and vegetation mature.
So far Im having 10 bronze cory and Im planning to get some more kind of cory. However, the mid level of the tank is really empty now and Im not sure neon or rummy nose can tolerate this kind of flow....
The parameter is: Temp 27C gH and kH is 1-3degree (Pretty soft water)
Any suggestion is welcome! I don't like something too big though
People are right, your tank is too small. Those fish grow really fast and can grow really big (You don't see those giantic fish often because most of the time they don't receive proper care and die before growing to full potential size)
For all goldfish type, they need to have food almost constantly. So feeding little is not proper care to be honest. They only seem fine because they are hungry and go crazily active when they see you as potentially they will have food.