Help! Very high ammonia or false readings?

Hi all, I noticed earlier today my shrimp were all hiding to the extent I thought they were all dead at first. I moved the tank slightly and realized they were all hiding around the filter near the top of the tank, so did a water test with the API liquid test kit and the ammonia went straight to the maximum! Nitrite was 0, and nitrate was also a bit high.

In a panic I did a massive water change and looked round the tank for dead shrimp. I found and removed 4, as well as some left over food and some decaying leaves.

After the changes, I tested again and ammonia was around 0.25. Obviously this wasn't perfect, but at this point I didn't want to stress them out anymore and decided I'd just do another big change tomorrow.

About an hour after this, I tested the water again and the ammonia reading was back up incredibly high. I thought this was very strange, as the tank is literally just cherry shrimp and a single nerite snail and shouldn't have gone up again that quick, so I did another test straight after which came up normal!

The attached picture shows the tests, literally done 5 minutes after one another! Any ideas what's causing this and what the actual ammonia may be?


For context, this tank has been set up solely with cherry shrimp for about 6 months with no issues. The only recent changes are:
*I moved the tank to another house a couple of days ago, so the tank was emptied to about 25% and then refilled
*I removed an old carbon cartridge out of the filter, but left the sponge in. I'm wondering if this may have removed some beneficial bacteria?
*Earlier today I added the single nerite snail, who seems fine. I didn't add any water from the bag he was in, I just removed him from the bag and put him in.


Sorry for the long post, I'm just wondering what is going on and whether I'm about to lose all my shrimp They've all come out of hiding now and seem to be acting normal after the water change, but the ammonia readings are confusing me!

Faulty ammonia kit. I put money on it. API is my fave test kit, but not for ammonia. I've had problems with the ammonia one, not the same as your problem, but I'm betting you have a test kit problem.

Get this one AquaCare Ammonia Liquid Test Kit, Aquarium Water Test Kit For Freshwater Fish Tanks (40 Tests) https://amzn.eu/d/0a5HBcPY

Or this one https://www.amazon.co.uk/your-order...es=&returnUnitMappingId=&shipmentId=U1prL311V

Also make sure that your ammonia regents are not expired. Especially if bought from a big box store, I have actually seen a case where such a store was selling such kits that were already expired.

Thank you both for your replies! I'll have a look at the ones you suggested @AJ356

I hadn't even thought about them being expired, my test kit is quite old so I reckon that may be the culprit!

Any ideas about the deaths, however, and weird behaviour? I did wonder whether they were false readings, but to have 4 sudden deaths made me concerned something was off.

One of the shrimp that died had a white ring around it, so I'm assuming a shedding problem? The other 3 were all fairly young shrimp. The behaviour was also odd as normally the shrimp are spread all over the tank, but before the water changes they were all just clinging to the filter and not moving much. After the changes, they seem more or less back to normal.

Check expiration date... but if you shake well they are good for a long time.

But your shrimps behaviors, death and their reaction after a water change, are the best gauge to confirm your test kit as good chance to be working.

The APi mtk in my experience, beyond 0.25 on the ammo test you can be quite sure it's there.

You need to give a lot more info, from size of tank, substrate to light, food to water, decor to plants... How was that colony going ? How many ? A photo with that ???

Your readings could come from overfeeding to dead shrimps decaying or both. Your high ammonia and absence of nitrite at the same time might also show a problem in the nitrogen cycle.

Something could have created a step back in ammo bacteria population... If you have some starter, you should start dosing the tank for a while. They are not perfect, they help a lot.

But whatever, You must keep changing water until it settle. 2 ppm is high for shrimps, But I seen they can also survive that.

If you can vacuum your substrate as much as possible at the same time, that would help a lot.

Not believing your test kit while you have an ammonia spike going on is (censured)... And Yes, it can rise back in minutes.

The comportment of your shrimps clearly shows that, you did the right thing to do a water change, that probably saved them... And might have to do more.

The tank is about 35 litres and has been running for 6 months. I'm using a fine aquarium gravel with just a couple of plants (not sure what they are, sorry!). Food wise, I'm feeding King British algae pellets and giving half a pellet every 3-4 days. The colony started off as 6 shrimp but has now grown to at least 30 when I last counted (though I reckon there could be more!), with shrimp regularly being berried. The shrimp were actually taken from another established tank I have, which had been running for about a year. I have noticed very few deaths since starting the shrimp colony. I've also never had any issues with spikes or crashes before, my ammonia and nitrite has always been 0 since cycling the tank.

I'm certain the dead shrimp had only happened a few hours before, as when I checked the tank this morning everything seemed fine. There were some dead leaves from the plants which I've removed along with the dead shrimp.

The only thing I can think of that may have affected the bacteria is when I took the carbon filter out. I left the sponge in the filter, but perhaps removing the carbon part also removed a chunk of bacteria?

I actually ordered some safe start as well as Prime when I first saw the spike to try and help manage it all, so I'll start using those tomorrow!

I'll definitely keep an eye on them to look for any more signs of a spike, and I reckon I'll try and get a new test kit tomorrow to try and get a true ammonia reading. The readings on the image were only taken 5 minutes apart, with the normal one taken after the higher one which is why I'm thinking the readings may be off. Something was obviously wrong initially though due to the behaviour and deaths, I'm just skeptical whether it was as high as the test said as it was telling me the ammonia was over 8ppm.

I went up to 3 ppm with a shrimp and it survived, 8 seems rough a bit...

But a spike, can give multiple times the maximum reading of the test kit before you diluted the water enough with water changes to have a positive reading = under the max.

But your observation on the Carbon is probably it, while depleted, carbon porosity provides an incredible surface area for bacteria, and suddenly removing all of them has certainly it's impact.

So I've just checked on them again and there's 3 more dead in there Is there any diseases that can cause red patches on their backs? All three that I've just seen dead have the same red bit. I've attached a photo but it's a bit blurry, let me know if you need a clearer one! The shrimp are also mostly at the top of the water again, so there must be something going on I'm just not sure what!

The ammonia bottles actually don't expire till 2025. I've just done another ammonia test and it's reading the same as last time (kind of between normal and the lowest option). I've just done about a 30% water change again .

I'm really at a loss here about what's going on. Could it be something with the nerite snail I added today?

Regarding the bacteria, do you think it would be beneficial taking a sponge out of another tank and putting it in this one until the safe start arrives tomorrow? My only concern is the ammonia doesn't actually seem to be have gone up, so is it a bacteria problem?

I'm extremely saddened to tell, that your shrimps are suffering from acute branchial chamber irritation. It reached the point of internal bleeding.

It is certainly caused by the atrocious ammonia readings you got...

There is not much you can do now...

I still don't understand, your feeding habits shouldn't have overwhelmed the tank at this point so fast.

Edit: considering the removal of your carbon cartridge.

Thanks for your help, unfortunately there are quite a few dead again this morning

I'm actually wondering whether my first ammonia was actually that high in the first place, or whether it was a faulty reading. When it first read at 8ppm+, I probably did about a 50% water change, filled it back up, then another 50% change. Wouldn't this have brought ammonia down to 2ppm (or more if ammonia was higher than 8) and NOT normal/0.25?

I've done another reading this morning, and ammonia hasn't risen at all. I would've said it may be something in the tap water or that the hardness isn't right for them... but I have 2 other tanks which have cherry shrimp in and they're both doing absolutely fine.

I'm going to remove the remaining live shrimp and fully drain the tank and gravel vac the substrate as much as possible. I'll then put them back in and see how things go as I'm not sure what else I can do.

Slight update, I've removed all remaining shrimp, there's about 19 left out of around 30 that I had 2 days ago.

I've completely emptied the tank as ammonia seemed to have crept up slightly again to 0.5. The gravel has been fully vacuumed and all dead shrimp/plants are removed.

Shrimp have been added back and seem to be acting normally for now and not hanging around the top of the tank. I'll be dosing the tank with Tetra filter active when it arrives later today to try and add beneficial bacteria back in that I may have removed with the carbon filter, as well as Prime to try and neutralise any ammonia remaining.

Hopefully it is a case of removing beneficial bacteria that led to an ammonia spike, and with the filter active and monitoring ammonia we'll be back to normal soon. What is weird is that it seems to have wiped out mostly adults, as from the 19 I have left they are all juveniles/babies apart from 2.

I'm still at a loss as to what might've caused the ammonia to spike so quickly. Perhaps during the move I disturbed some gravel leading to ammonia release? I suppose that still wouldn't explain why they started dropping yesterday rather than a couple of days ago, though.

Edit: Shrimp are back at the top again, checked ammonia/nitrite/nitrate and all normal as seen in attachment, so it seems ammonia is not currently the cause of the weird behaviour. I've temporarily moved the filter to provide more surface agitation, and have a new one I will be adding today that is slightly more powerful to try and provide more O2 in the tank in case that's the issue. Will be dosing the prime and filter active now and hoping for the best.

How is it going ? Was it the ammonia rising again ?

Hey it's going really well, no more deaths since my last post! Ammonia hasn't spiked again at all, so it seems whatever the issue was has resolved! I'm not sure if the beneficial bacteria was the problem and the filter active fixed it, or whether it was an O2 issue and the more powerful filter is helping add more O2, but it seems to be going really well atm.

I'll be leaving it another week or so and then transferring some more shrimp from my old tank over to help build up the colony again.

Thanks again for all your help!