This is just not my week with fish it seems. I had my platy get sucked up into the filter (the intake fell off somehow and I didn't realize it until it was too late ) and unfortunately she passed, and then I had a cherry barb go missing. And my betta, Lewis, continues to rip his tail by being clumsy around his tank. Sigh. /rant. Anyways, I finished re-setting up my 20 gallon on Sunday morning. I basically had to tear it down and redo everything, so I was in a bit of a rush to get it done. I kept my fish and the plants in a 10 gallon w/ the filter while I set it up, so the filter was constantly running therefore I had a strong, years worth of good bacteria going into the new tank. So I got everything set up properly, plants planted, filter running, and moved the fish over. I will admit and say it was probably overstocked for a new tank (6 cherry barbs, 2 juvenile platys, 5 glowlight tetras) but there was nothing else I could do really. However, the filter was put on the new tank so I had a strong colony of bacteria moving over, plus the addition of plants from the cycled tank should have been enough to manage the ammonia levels. I've done this before in the past with no issues and no fish lose, so I didn't expect any problems. However earlier tonight, I tested my ammonia levels and they were the highest I've ever seen. I use the API liquid tests and it was showing 8.0 Ammonia. I didn't check Nitrite because I panicked and begun an immediate 80% water change. I was going to retest the water when I wake up and do any needed water changes. Now I'm left wondering how on earth it got that high in the first place. I 100% understand how cycling works so I know ammonia is to be expected in the start, but I never have actually seen it get that high. And I'm not even sure what could be causing it to sky rocket like that. The filter is meant for a 20-30 gallon tank and was cycled for over a year, so it should be powerful enough to help cycle this tank easily. I know the bacteria still needs time to grow throughout the tank, but I thought the filter + all of the plants would manage my levels until it fully cycled. I've done this twice with the same fish, filter, and plants before and the highest ammonia levels I ever received was 0.5. The tank finished cycling within a week. The weird thing is, my fish didn't seem affected. I did notice that they were hiding and staying on the bottom more, but I figured they were just stressed from the move. That could of been signs of ammonia poisoning, but overall they acted normal. No gasping, no red gills, and they were eating and swimming normally. The only reason I was intrigued to test the water was because of the normal ammonia smell you get when a tank first starts up. I'm honestly shocked they even are alive after having those kinds of ammonia levels. :S I feel pretty terrible that I put them through that. I'm still in shock honestly. And now I'm worried that the cherry barb that I had mentioned early (it went missing and I haven't been able to find it) might have somehow gotten lost in the tank and died, therefore is contributing to the ammonia spike? I've looked for her everywhere but couldn't find her, so I had assumed she jumped the tank and my dog... well... got to her first. But now I'm wondering if she's stuck somewhere in the driftwood maybe, or even buried somewhere and is just rotting. I have no idea, and I've already set up my tank too much to tear it down again looking for a fish. And usually I keep Amano or Cherry shrimp in there to help clean up (in case something like this happens) but these parameters would instantly kill them. I have 2 nerite snails in there so they possibly might find her if she is indeed in there, but I'm not sure. These levels, they are absolutely insane guys. Ugh. I had basically planned on doing daily 50% water changes if needed and dosing Prime every 24 hours, but if I continue to get these extremely high ammonia levels, what should I do? I feel like removing the fish would only worsen them since I don't have a cycled tank to put them in. But now I'm worried they'll end up dying from ammonia poisoning. Gah I'm freaked out still. I just can't believe it got that high and they somehow survived. Is there anything else I can be doing or any guesses as to how it spiked that insanely high in less than 3 days? If it's any help, the substrate I'm using is a bottom layer of ADA Power Sand and Amazonia Aqua Soil. Not sure if that could be releasing ammonia or not..