Cycle crash

I have my axolotls in a tank that had been cycled a year ago and held a bunch of different fish and whatnot. It's now about 2 months since I moved them to the tank (without any other fish inside) and my bacteria must have crashed as I now have ammonia reading without nitrites or nitrates. I mainly want to know why so I can prevent it from happening again. Here is what my normal tank maintenance is:
2 5" lotls in a 10 gallon tank
20-30% water changes each week (I test the water at this time too which is when I noticed the problem)
Daily poo removal
I hand feed to prevent food getting lost and fouling the water
I have live plants and small shrimps in the tank too
I recently added another sponge filter (just floating) in hopes it could get some of the beneficial bacteria and speed my new tank cycle in a few weeks (obviously not happening now)
I've also been adding water that is slightly cooler (1-2 degrees F) at water change times since it is getting hot over here

I don't know if any of this would cause a crash but any info is appreciated. I'm also wondering what to do to help the axies. I'm changing the water daily to keep it below .5 ammonia but then the tank won't cycle (or will it?). I also don't really want to fridge them since they are still slightly underweight. I got them very underweight and have been working on getting them fat and happy.

I was going to move them to a larger tank (20 gallon long) this week but since the filters obviously have no beneficial bacteria in them I don't know what to do.
Should I work on cycling the bigger tank from scratch and keep them in the smaller one with daily water changes? Or should I put them in the big tank so the spikes are not as extreme? Also, should I keep the water cooler in the tanks (it's normally 68F or 20C)?

Thank you for any assistance. I'm so upset because I am super OCD about taking care of my babies and this was not in the list of possible problems at this point in the game.

Cycles are very fragile so I'm not surprised it would have crashed over a YEARS time. You should be testing your tank regularly (like every week) to make sure the cycle stays intact.

A number of things can cause your cycle to crash - rapidly changing PH, rapidly changing temperature, accidentally adding chlorine to the water, etc. The bacteria don't like changes in their environment.

The tank will still cycle if you do daily water changes. This is called fish-in cycling. Keep the ammonia below .5 like you've been doing and it'll be fine.

(I'm glad you're upgrading them - a ten is too small for even one adult lotl)

Axolotls need temperatures BELOW 20c, (16-18c) so yes keep the water cooler. You need a fan or a chiller.


What I would do is work on cycling the big tank separately with pure ammonia - the bacteria colonize faster in higher temperatures and if you put the little lotls in there now it would take longer because you, again, have to keep the lotls cool at 16-18c.

Do daily water changes in the ten to keep the toxins below .5 ppm.

Thank you so much!
Yeah they were supposed to go into the 20 initially but someone left the CO2 for the plants on too long and killed the tank. In a few more weeks I'll have all the tanks going and everyone will get their own 20 longs which will make for some happy axies They get their own room now..... I think I have a problem!

HannahMarie said:

I'll have all the tanks going and everyone will get their own 20 longs which will make for some happy axies They get their own room now..... I think I have a problem!

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haha - Welcome to the club