Danio Behaving Odd

[craig855s]

OK im two months into this hobby and i added 4 leopard danios on thursday, i now have white spots (tiny pin sized white marks on 1 of my harlequins-3 marks)

anyway, i've raised temp and added just over 2 tablespoons of salt per 5 gallons of water. And today one of my leopards (which has an upward curve in its spine and has done since i got it home,never noticed it in the tank at the LFS but it was obv there)

Said fish is now swimming alone,often keeping still in the water and moving fins quite a bit,also it has rested on the gravel and rubbed against it a little bit, anyone know what is wrong?

Water stats are

Ammonia - just below .25 (currently fish in cycling,water changes to keep it below .25)
Nitrite - 0,yet to spike with tank only being a few days old
Nitrate - 8
PH 7.4

 

[craig855s]

Danio died quickly after making that post after lying face down on a plant for a few minutes..Got it out the tank very quickly and into ice water to ensure its heart had stopped before being flushed.

 

[WILDER]

How old was the fish as a bent spine can be old age.