2 Fish Dead In Three Dyas

[NewbeeSteve]

I have had 2 fish die in 3 days, my Gourami and my Koi angel fish. The fish didnt get put in for a week after i cleaned it and they have been fine for 4 weeks now. What could be causing the fish to die? I added my danios a week ago and all of the other fish are fine and happy. Also done a water test nitrite is curently at 0.5. Any suggestions?

Also is it possible that I have to do a fresh cycle, fully clean and cycle the tank like you do when its new?

Any help or suggestion very welcome

 

[mark4785]

Gourami's are tropical fish and so shouldn't be mixed with a cold water fish (i.e. Koi).

It's likely the Koi died from shock of being introduced to warm water, especially if it previously residing in cold water and was literally dropped into a high temperature aquarium.

If you have completed a fishless cycle and were able to achieve an ammonia and nitrite level of 0ppm 12 hours after dosing your aquarium with a source of ammonia (typically pure liquid ammonia) and now find that the nitrite level is becoming unreasonably high, my suggestion to you is to do several small water changes until the nitrite level goes back down to 0 ppm and cut down on feeding. Your stocking level and the way you clean your aquarium may also be contributing to the high nitrite level; for instance, if you clean your filter media in tap water, this typically inhibits your filter bacteria from lowering your ammonia and nitrite levels. If you have a Koi in an aquarium, this is highly likely to cause fluctuations in ammonia/nitrite levels since it produces a lot of waste.

 

[fluttermoth]

It's a koi coloured (ie; black and orange on white/silver) angel fish, mark, not a carp.

 

[mark4785]

It's a koi coloured (ie; black and orange on white/silver) angel fish, mark, not a carp.

Oh, I'm sorry. Koi have many colours so I didn't take it has meaning koi-coloured.

 

[maisy12345]

Hi,0.5 is to high a reading for nitrites,what`s your ammonia reading,suggest you do daily water changes and retest after each one to make sure readings are 0,also feed everyother day until readings are down to 0,good luck.

 

[NewbeeSteve]

Ok done a 50% water change and added 3ml of fresh start to help de-chlorinate and also 1 ml of filter booster at 8pm last night. Just done a test now and the results are:

Ammonia: >~0.25ppm
Nitrite: 0ppm
pH: 8
Water temp 28c

Seems to have gone back now. Also found out that the Koi Angel fish was almost 4 years old due to the inlaw having the tank and him 3 years before she gave it to us ! Also the gourami was bought from pets at home so i dont know what age he was but both of them died from there. Mabey because of having only 2?

Looks ok so far definatly going to keep investigating though.

Thanks for the help