death

Two days ago I checked in on my tank and found two headless guppies. I figured my population control betta had finally gotten to work, but today I found two more dead guppies, and these were whole.

I've had a lot of what I thought was brown diatoms on my plants, to the point that I think my java moss wall is practically dead. My water parameters were normal last time I checked; I always have a bit of ammonia but since I use Prime it isn't toxic. Today the nitrate is 5 which is normal for my tank and the nitrite is 0.

I've moved the three remaining fish to a separate crappy two gallon tank of sorts until I hear what I need to do next.

:help:

I'll go in today and test the ammonia - it is 5 ppm nitrate, which my tank has always had even though I do a 40% water change every week.

The tank is pretty established - I've had it for almost two years, and the parameters have stayed pretty consistent, .25 ppm ammonia, 0 ppm nitrite, 5 ppm nitrate during the past few months I've been testing. The fish have been around almost that long, but the dead included adolescents and older fish, so I don't think that they all got old at once. There were four bodies that I found, and I honestly haven't been able to count my guppies in a while, so I'm not sure if there were more earlier.

It's the recent change in the plants that has me concerned as well, they're covered in the brown stuff, yellowing, and the java moss has gone brown/dead. I started putting Flourish in the tank a while ago, but I've only dosed twice a month or so ago, and then once in the last week when I saw how badly the plants were doing.

I was also out of town so they went about 11 days without a tank cleaning instead of the usual weekly, so that probably did it. I guess I assumed that since they were alive when I got back that the trip hadn't hurt them, but maybe it just took time for them to die.

I use Prime to detoxify my ammonia, but my test kit still shows the detoxified chemical as being ammonia, and I always give a 1.5-2x dose with new water to dose the entire tank. So I'm not sure that ammonia would do it - would that explain the plant problems as well? And the brown stuff everywhere?