Arowana stressed

[MetalJeans]

i moved my 5 inch arowana into my 300 gallon 8ftx3ft tank after i suspected its previous tank was causing him not to grow and to dart around , but after moving him into the 300 he bends his tail, and doesn't swim at all, the ph is 6.5, no ammonia, nitrate levels are at 0 ppm and nitrite is at 0

 

[NeverFadeAway86]

do you have alot of plants in the tank or just do a very large water change ? seems odd that nitrate would be at 0 unless it was one of those two things. has this tank been setup for awhile ?

 

[MetalJeans]

do you have alot of plants in the tank or just do a very large water change ? seems odd that nitrate would be at 0 unless it was one of those two things. has this tank been setup for awhile ?

when we do water changes we do 30%, we do have small live plants in the tank , the tank has been set up for maybe 6 months now , other fish in the tank are fine , we found out if we turned the lights off he starts to swim a bit .