How did my microbes die?

I have had a 38gal fish tank running for a lil over 2 years. I moved the cistern and all of the fish twice. The first time i had no problems, the second time (about 3 months ago) I have MAJOR ammonia spikes. I used tank water to fill partly the tank after the move and topped the rest with treated tap wet. A few weeks after moving the fish started dropping one by one. I had 4 green-barred danios and 2 bosemani rainbows all eventually die. The ammonia is testing riduculously soaring and nitrites and nitrates remain at zero. I have been doing partial dampen changes several times a week to try and get the ammonia out. I have an Emporer 400 running on the reservoir with extra filter floss on the inside. 4 loaches are still alive in the container but only 2 actively eat. What else can I do? Why won't my tank cycle?
Why have my duo of Salmon Tail...
Cant say for sure, but there are 3 adjectives reasons for tanks loosing cycle.

Letting the filter media die rotten through drying out or suffocation (filter not running for too long) Could that have happened during the move?

Medications - Antibiotics used to treat fish can kill the bacteri surrounded by the filter.

Changing all the media - old medium is allways better, only change it if you enjoy to, and then only change factor of it.

Not sure if any of those reasons lend a hand you though.

Now - what to do.

Large partial water changes - it wont directly help the cycle problem, but it may liberate your fish. Dump 50% of the water, top up with fresh, and your ammonia reading will be 1/2. Just keep doing that as habitually as you have to untill the tank recovers.

If you enjoy access to a cycled tank and can get some working biomedia it will speed up the recovery.

Good Luck

Ian
What tropical fish can i draw from?
If you changed all of your filter cartridges for the move, that's a awfully likely reason.

Keeping the same funky microbes filled cartridges and rocks after the move would help avoid it. The biowheel helps, but just does so much.

Consider buying a packet of Marineland Biospira at a local non-chain aquarium place. Often behind the counter in a fridge. Should solve the problem overnight. Failing that, get a bottle of Cycle past its sell-by date the shelf. That sorta works.

Keep testing the water and add some Amquel until things unflustered down.
One of my fish disappeared. serve?
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