Fish dying

[erichillkeast]

You can buy tests kits for ammonia, nitrite, and nitrate.

If you don't know already, I would look up and gain a good understanding of the nitrogen cycle, that way I you will know what safe levels of all three are, and what would be causing the usafe levels.

In the mean time, I have a couple questions.

How big is the tank?
What is the total number of fish?
What, how often, and how much are you feeding?
How big and how often do you change your water?
What type of filter are you using?
Does it look like any of the other fish are sick (closed up fins, eye pop, ich, strange twitchy behaviour etc.)