Is my cycle ok


Fish Fanatic
Aug 19, 2023
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South West Scotland
I removed a 3D background from my 200L Ranchu tank last week as it was trapping rubbish behind it. I have had it in my tank since it cycled last September. I have today done a 70% water change as my Nitrate reading was 20ppm. My Ammonia and Nitrite readings were both 0.
Today as I was doing my water change I added a new poster background to the outside of my tank and put in 5 artificial plants.
After my water change my 2 fish were acting very strange swimming upside down, they looked as if they were dying. I added extra prime and aquarium salts. They have settled down but now they are acting very scared, the slightest noise or walking past the tank and the dart behind the plants.
Also my readings after my water change were Ammonia and Nitrite 0 Nitrate 5. Do you think my cycle has taken a hit because I removed a large background. If so should I get Prime Stability.
You say the ammonia and nitrite are still 0 so we could suspect a toxin. If you are sure you didn't forget to dechlorinate it could be the artificial plants. Remove them and do a large water change in case they introduced a toxin.
Thanks for you info. I pre washed the plants. And let them soak for a day, them left them to dry for a day before putting them into tank. Got them from a good supplier. Both fish are keen to eat. Could it just be the change of tank lay out. I added Prime when doing water change, admittedly I forgot to add it before I filled fresh water but realised and added it just as I had finished adding the water.
Ah, the reaction would be explained by filling with dechlorinated water then. As you have fixed it quickly they should settle back down now. Just monitor them and the parameters and report back if you're concerned.
Thank you for your responce.
Hope you are correct. With me changing the tank decor I just was out of routine. I quickly added full doze of Prime. Then an hour later after reading bottle instructions it said a double doze may be used safely. So I did that. Also I added a half doze of API aquarium salt.
Do you think I should add a single doze of Prime tomorrow. I am getting 1 Ranchu delivered on Tuesday I do hope I have not messed up my tank.
Do you think I should add a single doze of Prime tomorrow.
You should only need to dechlorinate when you do a water change.
Test the water. If the ammonia and nitrite are still at zero, then there is no need to use extra Prime.
Thank you very much for you help. Both fish this morning are looking okay, eating and looking less timid. Hopefully I am over a bad mistake that I will never do again.

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