Ammonia poisoning with 0PPM ammonia?

[Tholamew]

Hi Everyone! I'll try and be as clear and detailed as possible below.

The Patient: 1 Orange Laser Corydora, owned for about 1 year.

The Symptoms: Lying on it's side, gasping, red gills.

The Tank: 20 Gal Hex Tall, Aquaclear 50 HOB Filter (well established for over a year, 3 intake extenders and a sponge over the intake), 78F, 8 Gal water change weekly (last one done 6 days ago) w/ Prime. Lightly planted, Seachem Black Sand substrate, no new decor added.

The Water: Tested with API Liquid Test kit, Ammonia: 0PPM (The colour doesn't show a perfect zero, but I've never seen it read a perfect zero on any tank, and it isnt close to the .25ppm mark), Nitrite: 0PPM, Nitrate: 0PPM

The Tank Mates: 2 other (so 3 total) Orange Laser Corydoras (that have layed eggs around 10 times in the last 3 months, if that's relevant), 6 Celestial Pearl Danios, some assorted shimps (Amanos, cherry).

The Food: Sinking pellets, krill powder, crushed flakes. Fed once daily.

The Backstory: At the beginning of July (I believe the 3rd or 4th), one of my Corys was found belly up on the bottom of the tank. When I went to net him, he righted himself and swam away fine. He was fine all day. Next morning, he was belly up again, and when I attempted to net him, he righted himself and swam away. This went on for a week or so before my Dwarf Gourami started exhibiting the same symptoms. Eventually they both got to the point where they lost the ability to swim normally, and I decided to euthanize them (clove oil). Seemed like a swim bladder issue to me, but I found it odd that it would happen so quickly to two separate fish (I don't know swim bladder issues to be contagious). All other tank inhabitants seemed fine, and continued to be fine until yesterday afternoon. I came home from work to see another Cory belly up, gasping, except this one had gills as red as a tomato. I know this to be a sign of ammonia poisoning, however I did a test and got the 0PPM reading (see above). So I moved him to an isolation box, I dosed prime, and added some bacteria supplement just incase. I was unable to do a water change last night unfortunately. When I woke up this morning, he was still gasping, although not constantly, still laying on his side, and the gills were still quite red. I checked ammonia again, and again, 0PPM. I'm stumped friends! I hate losing my fish, and my daughters cry every time

 

[Laken]

I'm stumped too but I can offer a few suggestions...

Double check the expiration date on your test kit, if it is expired and the chemicals have sat for too long it could cause false readings. I know that's probably unlikely that your test kit is expired but thought it was worth suggesting.

I'd bring the water to your LFS to check, just for a second opinion.

Also get readings on your ph, nitrites, and nitrates.

That's the only things I could think of. Good luck with your fish.

 

[Tholamew]

I didn't actually realize that the tests expired, so thanks for the heads up! They're good until 2024. I'll try taking some to my LFS, that's a good idea.

The Cory didn't make it sadly . I did a 50% water change yesterday and did another test this morning. pH-7.6, Nitrites-0ppm, Nitrates are reading 20ppm, and I'm still getting the same ammonia reading as before. I've included a picture.

 

[Laken]

I'm sorry you lost the Corry

If any more fish start displaying the same symptoms maybe look into bacterial gill disease (I wish I had thought of this sooner when I made my first reply). I'm just pulling at straws, trying to think of other reasons for red inflamed gills and gasping for breath that isn't due to ammonia. Here is a link with some information about it and treatment just an fyi in case any more fish show symptoms.

Your water conditions seem fine and the tank doesn't seem to be overcrowded, so I'm not sure what would have caused the outbreak if it is due to a bacterial infection, that's the only other idea I have. Hopefully all your other remaining fish continue to be happy and healthy.

 

[Autumnsky]

If you don not already do this, double dose the Prime in case of Chloramines in the water.

If you are in summer, often additional algaecides /chemicals can be used in the water supplies to kill off excess algae, or water lines can be flushed as well.

It does appear you have some ammonia. Stress can be caused by any number of things, even a bit excess ammonia compounded with a mate or other fish chasing it around.

This can cause parasites to get a hold on the fish with a decreased immune system.

Very sorry about your losses.

You might just check the tap water for ammonia as well. In case you have that already in the water before you even begin. That way you will know you will need the extra days after the water change dosing Prime to neutral the ammonia.