Not until the tank has cycled, unless you just want to keep killing fish.

Did you do the 50% water change yet? If not, do that and test for ammonia and nitrite. Post what your readings are.

I really really screwed up once with a marine tank. The fish in the tank were breathing heavy in a matter of hours/minutes and two died in hours. Ammonia with the api test kit was very very "pegged". Several other fish were "on their last legs" with one actually horizontal instead of vertical. I removed as many fish as I could to another tank and the sick fish recovered in a matter of hours/minutes with the horizontal fish back to the vertical position. I treated the tank with prime per instructions for a 8ppm ammonia level. The 2-3 fish that I could not get out survived. After treatment total ammonia was still over 5ppm but free ammonia was .25-.5ppm or so. Ammonia continued to peg the apu test kit for a week until I took action. After that ammonia dropped to 0 in 2 days. Then nitrItes pegged the kit for a few days and nitrAtes started to rise. PH also crashed for 3 weeks. then nitrates dropped and ph rose.

I returned the fish to the tank after ammonia dropped down.

this all occurred with no water changes.

So IME if you have very high ammonia the fish will be breathing heavy almost immediately and die in hours. Can't say about lower levels but from my experience the danger from ammonia is apparent almost instantly. But it can take hours or days for ammonia to reach those levels. In my case I accdentially added a toxin to the tank so the ammonia was there instantly.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

So how is the tank doing now?

Its still has the same off the charts ammount of ammonia as last week but the two gold fish are still alive. I did the big water change and that didnt seem to affect it much either.

I went to the aquarium store again yesterday to talk to the same guy I've been working with. In a last attempt I replaced the filters (I guess sometimes you can get bad ones?) and bought some ammo-chips (looks like gravel but is supposed to take out only ammonia). I just changed the filters, put in the ammo-chips and did another 20% water change about 2 hours ago. The ammo-chips dont say how long they take to work but ill let you know if I notice them doing anything.

Well....I know it has been a while for your cycle, but replacing any filter media may have been a bad idea. Hopefully you didn't replace all parts if you have multiple filter pieces. Your filter will house much of the needed beneficial bacteria, both during and long after your cycle.

Have you tested for nitrites lately? How old is the test kit you have for ammonia? I would do a 50% water change tomorrow or the next day.

Not sure how your fish have survived through this, but they seem pretty hardy.

Cowboy, I am in the middle of my first fishless cycle too. Just in the past few days, about two weeks into the cycle, I got my first nitrite reading. It was, and remains, off the chart. I dose daily (once the ammonia started being consumed) to take the ammonia level to 1-2 ppm. It is consumed in 24 hours. I started the cycle at about 4-6 ppm ammonia.

BTW, I keep the hood on my tank closed and only added Prime water conditioner when I first set the tank up.

If you don't watch it your nitrite will peg and stay there for a long time - if you keep up daily doses. Personally, I'd back off to half of your normal dose and only every 2-3 days. Just a rec. Speaking from my most recent experience. Had to do 3 water changes at 50% or greater (125g tank) to get my nitrites down to levels that could be controlled.

I tryed it all when I first started my 10 gal. 3 months worth, 10 fish and a lot of additives. OK..Here's my snap. Hard water..I have it..off the charts, and it's city water. 8ppm+ off the chart ammonia. Had to age my water til it had no ammonia before the ammonia in the tank would break down and start cycling. The additives wouldn't work because the water was so hard. After I figured it out in 3 weeks - 0 ammonia 0 nitrites 30 nitrates 6.2 ph and still hard water. But all my fish do fine in it and no problems with my plants. Just another thought from my experience. Oh.. both my tanks will go up and down a little on the readings, but they both are a little overstocked. DING..almost forgot...I also left the tank uncovered and plenty of light and warm water. 80+ untill it cycled.

I have also similarly problem. all replies are welcome.
Thanks for this great sharing.

I cant wait to start mine!

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Jons4real

http://www.youtube.com/user/jons4real