Listen to this fish tail and offer advice

[K2pizzle]

I purchased my 55 gallon tank about 8 months ago. I mistakenly cycled with fish and everything actually went pretty smoothly. The tank was fully cycled and I was slowly stocking. Then after things running smoothly for about 4 months something happened and wiped out my entire tank. There was absolutely no change in any of the levels and most of the fish showed absolutely no signs of sickness. It was absolutely horrible. There were some fish who showed signs of columnaris but as previously mentioned most of the fish showed no signs of injury or sickness. So i took the last remaining survivors and put them in my hospital tank. I used a disease treatment and those fish are still swimming.

As far as the main tank, I emptied it, cleaned absolutely everything, and purchased the Cadillac of filters. So my tank is a 55gal tank with a Marineland C-360 external canister filter (made for 100gal tanks). I have an air pump which feeds a bubble wand and airstone. the tank is heated and has gravel substrate and artificial plants and I will be adding real plants in soon. I did the fishless cycle and added ammonia to the tank three weeks ago. I monitored the tank but not as frequently as I should have. But now the tank levels are reading as follows:
Ph 7.5
Ammonia 0
Nitrite 0
Nitrate 0


I use the API liquid test kit. Thinking the tank had cycled I added pure ammonia and let the tank run for 2 hours, then tested the water again and got the same readings. (Ammonia,nitrite, nitrate all 0)


So my questions are:


Does this mean the tank is cycled?


Should I perform a water change before stocking?


Do you think it's safe to reintroduce the fish that were part of the initial tank disaster to the new tank? They had all been treated and have been in the hospital tank for more than a month but a few of them seem lethargic. I am terrified that the fish are still carrying this disease!


Thanks for the help and once I get a few fish in I'll try to add pics of my beautiful tank!

 

[Wiggles24]

That's not right it doesn't sound cycled. Unless your tank is VERY heavily planted. Forgive cuz I always mix these up but I believe it's nitrites
That should have a reading, that's what converts your ammonia. What are you using to test your water?

 

[librarygirl]

No, if you were cycled you'd have some nitrate. How much ammonia did you add? Here's a calculator that will tell you how much ammonia to add: Calculator (scroll down to where it says ammonia calculator). Here's the fishless cycle guide if you haven't seen it: http://www.aquariumadvice.com/forum...guide-and-faq-to-fishless-cycling-148283.html

As for the fish, what do you have now and what size tank is the QT tank? Have you been testing it for ammonia, nitrite etc? If fish are lethargic I'd start with parameters to make sure there aren't any toxin spikes going on. Other than lethargy, are they showing any other symptoms? Are they eating?

 

[TOMatt]

How new is the API test kit?
At first I used the old one my friend gave me with the tank, and the results were all 0. The test kit had expired.