Thread: Hospital tank, High Nitrite!!

What water changes are you doing mate

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Originally Posted by RevinKevin

Hi all, I have one of my koi that has dropsy and has been in a 400 ltr tank now for a couple of weeks.

I have heated to 25°c, added salt to 0.6% and added acrliflavin now on the second dose (after 10 days) and seems to be working.

I am now getting high Nitrite levels (currently at 5ml/g).

I have another fish in for company, and not feeding.

Ammonia 0
PH 7.6
KH 8
Nitrate 50
Nitrite 5

Filter is a fishmate15000, with some K1 media added from main pond and added some microfiber lift.

Any suggestions to help reduce it please.

The maximum tolerable nitrite level for koi is 0.2 mg/L so your level is 25 times that which means that you have an immature biofilter and the nitrite will currently be making long term detrimental changes to the haemoglobin in their blood which is reducing it's ability to carry oxygen.

Although you're not feeding, koi excrete ammonia through their gills with every respiration cycle so you should reduce the level to below 0.2 mg/L with water changes asap then use water changes to keep it below that level.

With such an extreme level, I would suggest increasing the aeration as much as is possible and do 50% water changes every day (with a dechlorinator) and top up the salinity and acriflavine to keep them at a constant level during the treatment. When the nitrite level has fallen well below 1 mg/L, you should still do daily changes to keep the nitrite level falling towards the maximum level of 0.2 mg/L but you can use your judgement as to the amount you change.

Ask if that isn't clear or if you need more advice as the level falls.

I'd suggest keeping the salt level constant until the fish has recovered. The acriflavine will have already cleared any bugs that were in the water from when you transferred the fish and it can't do anything inside it to help with the dropsy so, unless anyone has any other ideas on keeping the level constant, I wouldn't add any more as a top up when you do the water changes.