Can fish die even several days after a nitrite intoxication?
I came home the other day, and more than 10 fish had died. I then immediately carried out a water test and noticed the nitrite level was too high. Then I did everything to lower the value. But today the level is alright, and fish die nevertheless. What shall I do?
the nitrite level should by all means checked daily (twice if possible). sera toxivec and sera bio nitrivec provide detoxification and biological activation, respectively. Be sure to generously change water right away in case the level rises again - if necessary, twice daily 80 % each (temperate the fresh water and condition it with sera aquatan, sera toxivec and sera bio nitrivec).
Additionally, it is important to find out and remove the cause (e.g. filter or pump failure; unnoticed dead fish or apple snail). As a safety precaution, the filter should be activated with sera bio nitrivec (see above, please) even if it has been biologically active already.
Unfortunately, a nitrite intoxication can lead to deaths also after several days, even if the level has sunk in the meantime. Background: Nitrite inhibits oxygen transport within the body, and even a not immediately fatal dose may have lead to severe and unfortunately irreversible organ damages that then kill the fish after a few days.
Dr. Bodo Schnell