Ammonia Spike Help Please


Valued Member
Reaction score
1 year
Hi there.
So iv had a 20 gallon planted tank for about a year now, never any problems, so i decided to up my game a little bit and got a 60 gallon.

Iv had the tank filled for 6 weeks now. I had 10 bronze cory catfish (large) from the beginning, probably a week after filling the tank, and everything was going fine.

I added 10 tiger barbs 2 weeks ago and suddenly i have an ammonia spike.

Iv lost 6 of my bronze corys and 2 of my tiger barbs.

Iv been dosing with api's ammo lock for a week now. Performjng 20-30% water changes. And i still have a 1.0 ppm reading for ammonia.

Can someone please offer some suggestions on how to fix this issue


Well Known Member
Reaction score
1 year
Time & more water changes. Sounds like you overloaded the beneficial bacteria in your filter by adding so many new fish all at once. If you had done 2 groups of 5 a week or two apart it probably would have been more manageable.
Are you testing parameters in your tank (API Master kit or similar?)? When I was first stocking my tank my goal was to have parameters stable (0 ammonia & 0 nitrites) for a week before I added new fish.

So for now sounds like you need to do some back to back large volume water changes (50-70%) to get the ammonia closer to 0. Then follow this guideline:
If ammonia # + Nitrite # > or = 1.0 do a large volume water change, dose with dechlorinator (ex Seachem Prime if what I use, I am not familiar with ammoLock) and retest in 24 hours.
If ammonia + Nitrite < 1.0 dose with Prime & retest in 24 hours.
Since Prime detoxifies Ammonia & nitrites (plus heavy metals I think) up to 1.0 this should prevent more mass deaths.
This is a stinky way to start your new tank, sorry. Hopefully it will be smoother sailing from here.

Also - check your source water parameters! This morning I had 0.25 ammonia following a 40% change on my established tank, I tested my tap water & it is back up to 1.0. Sigh.
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