Originally Posted by gooner

im having 2 ft tank with plant and fishes inside..
using biofilter.. put outside the balcony.. the tank been doin well pass 3 month with few guppy inside.. i add fertilizer every week to reduce the nitrate level of the water.. and add water when water level drops.. change water within once every week.. i add ketapang leaf too to make acidic water so tht i'll get lesser algae attack and prevent parasite, fungus..

everything goes well until i add 10 guppy inside the tank..and others fishes like tetra and mouse fish.. thy looks ok.. like today i saw them swim freely, then the next day, i saw one fish die left with bone.. it jus die in a nite.. then th next few day.. it happen one by one.. i input 10, loss 10(one by one sometime 2).. !! until even i do water change(jus change the water.) it settle with few fishes surviving until now..

my question is wat make this happen? thy din show any sign of diseases.. and yet die in a nite.. water quality?