Why.......

[james nash]

HI all why are my glow lights and cardinals at the top all the time my water is. ph(7)nitrate is highish and nitrite is ok and ammonia is good and oxygen is good and some of my cardinals are dying the tank has been set up for about two months help

 

[guppy_man]

maybe there is not enough oxygen in the tank so they are trying to get some from the surface.

 

[The-Wolf]

symptom(s)
fish hang around the water surface / stay on the bottom and may lose equilibrium.
They are lethargic and don't eat.

possible causes
1 ) Acute poisoning. Water should be tested for core parameters and fish examined for signs of severe parasite or bacterial infection. If these are negative carry out a 75% or more water change on the presumption of some (as yet, unknown) toxin.

2) Low dissolved oxygen levels.

3) Peracute bacterial disease.

hth