Two of the five angelfish I have are probably not going to make it through the night. They wont leave the surface and keep gasping for air. I have a DIY CO2 on a 60 gallon so i know i didnt gas them.
I did a weekly water test and my ammonia level was at .5 ppm, my nitrites at .25 ppm, and my nitrates at 80 ppm. I dose via the PPS pro method and this is the first time things have looked this bad. I did notice that my ammonia level rose from 0 ppm to .25 ppm ever since I started this method.
I did a quick 50% water change but the only thing that really changed was my nitrite levels. They went down to 0 ppm. I think my nitrates may have gone down to 40 ppm but I can't really tell bc 40 and 80 ppm look too much alike.
None of my other fish are showing any symptoms. My angelfish aren't wild caught either.
I think I'm going to cut back on dosing to every other day and see if that helps. Anyone have any other suggestions or input?

50% wc netted you nitrates between 40 to 80? I'm not a smart man but 80 ppm nitrates is too high for anything to be comfortable. I would cut all dosing and continue changing water until you can calibrate your test kit and find out exactly what is going on. With your levels being that high I have to ask what other livestock you have in this 60 gallon? Are you overstocked?

You need to figure out how much NO3 you are introducing in your tank with your dosing. Your NO3 is high because your plants aren't consuming it (maybe not enough CO2), or you are dosing too much.

Didn't think about consumption, tetra is right. If you don't have the Co2 in the tank to support consistent NO3 uptake then you could be harming your fish.

Is the tank cycled?
how old is it?

.5 for ammo is enough to kill so A. your tank isnt cycled or had a major breakdown or B. your water *tap* has at a lethal enough dose for them. test your water your doing the wc with an come back. i highly doubt its your dosing of ferts if your ammo is at .5 unless your dosing something that has ammo or is breaking down to make ammo. also if your tank is overstocked it can cause a crash from build up which leads to ammo levels building up to those levels. so more info is needed to guage whats wrong but id doubt its your ferts!

In general, Ammonia should keep at levels below 0.02 ppm, especially if pH is alkaline. Sustained levels this high (0.5ppm) may cause problems long-term but shouldn't kill fish outright.

Thats right I didn't even think about the ammo content, that is a much bigger problem then the nitrates at this point. That leads to the most important questions that need to be answered and they were already asked by green.

Step 1. Stop dosing. Turn off the co2. Lets fix things we can.... What is your water temp? Do you have any surface agitation. Lowering temp into the 74-75 range and adding an airstone will help them cope.

If ammonia and nitrite are present, this means you are not cycled or have a mini cycle going. What is your filter maintenance like? You can't remove all of the filter media, so be sure to have a separate bio media from the mechanical aspect because of this.

Water changes, a few 50% changes at LEAST once a day, are helpful and essential to survival.

Maybe not outright but prolonged exposure....? I'm going to assume, no one kill me here, that as suspected these fish were introduced immediately following the tank setup. That typically means ammonia burn/gill issues and ultimately death.

I gotta roll with stocked on this one

+1

I ran head long into this for about a week a couple years ago ending up overstocked and rushed the loading on a tank. NH3/NH4 can be chemically locked down not to hurt the fish up to around 2ppm. It will still test positive and continue to cycle in tank yet not burn the fish. AmQuel or Prime.

Simply adding salt at doses low enough not to damage plants can neutralize the effects of NO2.

Do I stock tanks showing either? no
But the baby and the bath water can be dealt with when an error is made.

fair enough

I only have 5 angelfish, 3 otos, 1 bleeding heart tetra, 2 amano shrimp, and 1 cherry shrimp.
The tank has been up and running since June.
My filter is a 305 that was installed in August and hasn't been cleaned yet. I did think about replacing some of my mechanical media though.
My pH is at 7.4

Edit- I tested the water from the faucet outside of my house and from the sink and they have 0 ppm nitrates. I have to leve for work soon so I wont get to test my ammonia and nitrite levels till later. Also my lfs did tell me that the last order the put in for angelfish was a bad batch and I was one of the people that purchased some of them. If I knew this when I bought them I wouldn't have but I didnt find that out till a week after I bought them
Edit2- I found where my ammonia problem
Is coming from. It's from the faucet outside my house(.5 ppm). I guess I'll have to use the water from inside the house from now on(0 ppm).

ill put my money once you get the ammo nitrite level back at 0 your issue will go away, nitrates is rarely the first place ive ever seen issues with unless you just dumped a crap load of ferts but then you would already know about it. do a major 50%+ wc an let us know it you see inprovements id fill buckets an test them befor adding them to your tank just to be safe unless your confident that its at 0ppm, as most homes have one line come into the house an then split off for outside use off the main line idk how urs is set up but id assume im not to far off.