PWC today and water tests 1.0 ppm ammonia!

So I just did about 30% water change in my 20 gallon long this morning, just tested the water this afternoon and the ammonia is at 1.0! It has never been higher than .50 and that was only for about 2 days other than that it has stayed between 0-.25, I'm testing my tap water now to see what the ammonia is in that.
I don't know what to do though, should I do another water change to try to get the ammonia down? I dosed both the new water, and just now the whole tank to detoxify the ammonia.
I'm leaving soon for the weekend and am unsure what I should do.

My stock is;
3 male guppies
8 harlequin rasboras (new to the tank on Wednesday)
2 trilI cories (Had 6, 4 of them came sick from the LFS and died, just waiting for more to come up to up my school)

other parameters are;
0 nitrites
10 nitrates

 

So there's 0 ammonia is our tap water...

 

I don't know how to determine the exact cause, but I'm thinking the new fish are causing it by adding more ammonia to the tank than the beneficial bacteria was ready for. Don't add any more fish until you have 0 ammonia and 0 nitrites as they will either die or make the problem worse. I would definitely change the water again, because 1 ppm is very high for ammonia. I would also consider picking up an ammonia detoxifying chemical for emergencies like this. Is your tank cycled? How old is it? Other people can help you with stocking levels and compatibility of the fish, as there are many people here who are more experienced in those things than I am.

 

Adding 8 fish of any variety is a lot for any current bio-load to handle let alone because you already had a biological filter that wasn't yet strong (since you had ammonia before you got these fish). You'll need to do daily water changes to keep the ammonia down until the bacteria can multiply and catch up to handle the bio-load.

Do you have Prime and Stability or another bacteria in a bottle product you can add in every day?

 

So I did a 50% water change Friday before I left, dosed with Prime and Stress Guard (just as an extra precaution) I got home last night and everyone seems to be doing well (YAY) I tested the ammonia and it was between .25-.50. I'll do another PWC in a minute. I wasn't sure if the Rasboras would add that much ammonia that quickly. My tank is only about a month and a half old but it is cycled.

 

In a 20 long, the most I would recommend adding fish at one time is maybe 1-2 fish. If you had a 75 gallon or 125g tank, maybe you could add 8 rasboras at once. It's always better to go slow and add fish at a slower pace. The whole schooling principle does apply but fish will be ok if they are not in a complete school for a couple weeks.

 

Oh ok, yeah I had read to add schools at all together so that's what I decided to do. I want to get my Cory school back up to 6, which means I need 4 more. So would adding 2 over the course of 2 weeks work? My poor cories seem so lonely right now...

 

You could maybe add 2, check water levels for a couple days and see if you get any ammonia/nitrite spikes, wait a couple days, then add the other 2. But you should wait till you get over this mini-spike first and wait for things to get back to normal.