Help, silver dollar having seizures, other fish attack it

[FreshyFresh]

Any measurable amount of nitrites with fish in the tank means you should be doing water changes until it's 0ppm. 50ppm nitates is too high as well. I would not be adding any more fish until you can maintain 0,0,<20.

 

[Rbishop]

Any amount of nitrite is a problem.
Nitrate is a bit high for my liking, but considering this is a new cycle it's ok.

Maybe a stock issue?

Can't be a new cycle if what the OP says "they finished" cycling in the open statement...

 

[Rbishop]

I'd water change now and daily to keep measurable nitrites at zero.....