All My fish Died! I Thought the Tank was Cycled. What Could be Going on Here?

[Punkrkgrl]

Ok my fiancé had a 55gallon tank that he stopped taking care of even though there was a Chinese algae eater living in it! (I know that's terrible) anyway half the water had evaporated the filter hadn't been running for months and the algae eater was still alive! I begged him to show me how to clean it and let me take it over, he agreed.
First we filled the tank with more water (added dechlorinator) then turned on the filter and got a heater. We left it run like that for about 5 days and then I needed to vacuum the gravel it had not been cleaned in at least 6 months. I cleaned it well and then changed out almost half the water again with the dechlorinator. I set the tank for about 78 degrees I'm planning on keeping angels, I thought using the old filter bio wheels and just adding water and cleaning a previously set up but severely neglected tank would have instantly cycled it. I used test strips and everything looked good (I now know test strips are crap) I bought 5 angels, very small about quarter sized and acclimated them to the tank for a few hours before adding them, they looked good for about a week and then one by one they all started dying. I was doing 20% water changes every other day. I bought a master test kit with drops and tested the water, ammonia 0, nitrite 0, nitrate 80ppm at this point everything is dead so I changed over half the water to get the nitrate down and my fiancé suggested getting some zebras because they are hardy and see how they do for a couple months until the tank is well established. I went and got 5 zebras and a golden algae eater, within 24 hours all were dead. No signs of stress, all water tests were normal except the nitrate went back up to 80ppm about 12 hours after adding them. So again I changed out a good deal of the water to bring it down. The tank is now empty of fish. I feel terrible. I do not believe fish are expendable and I really thought the tank was cycled. Could it be that it isn't? And where do I go from here? I really want to keep fish and I'm absolutely dedicated to cleaning and testing etc I just need to know what I should do now? Do I need to drain it and start over? If so how? Please help? Here's some more info on my set up...

55 gal freshwater
Penguin bio wheel 350
Temp 78- 80 degrees f
Not planted
Ph 7.4 (that seems high but I've been warned not to mess with it too much there are some Pete granules in the filter but they have yet to help bring that down.)
Ammonia 0
Nitrite 0
Nitrate was 80ppm when the last zebra passed. Changed nearly half of the water and it was right around 40ppm.

What am I doing wrong? Was the tank just not properly cycled? Can I cycle it now without fish? Any and all advice is welcome. Please don't be mean I am a noob but I'm trying my best to do everything properly.

Thanks so much for any advice you can give me!

 

[bud29]

to the forum!

We all have to start somewhere - don't worry Outside of nitrates, your parameters look pretty good. I would check for any large pieces of decomposing matter - if there is a dead fish hiding somewhere, it will cause ammonia, nitrite, and nitrate spikes.

I would give the tank a thorough rinse, especially the substrate, to get all the dead matter out of the tank. The tank is without fish, correct? While soaking the filter media in a bucket of dechlorinated water, I would drain the tank and rinse the substrate in buckets of dechlorinated water. There is probably lots of fish waste in the substrate due to neglect, which is probably part of the reason you are seeing very high nitrates. Add the substrate back to the tank, refill the tank, re-scape it, etc. etc.

Here is a great guide to fishless cycling your tank. If you are constantly seeing nitrates, and not ammonia and nitrites, your tank actually should be pretty close to cycled, but give it a good read still

Hope this helped!