30 Gallon Tank Ammonia Poisoning without Ammonia???

Hey Community!
I really need help

In Short: one of our Corydoras is ill. He is lethargic and has difficulty swimming and with orientation. He doesn't move much but he will swim to the surface for gulps and doing that he collides with all kinds of decor and even the floating plants. After that he breathes heavily from exhaustion but when he calmed down his Gills doesnt move at all, or so lightly that i cant tell. His colors are dull and greyish. He just looks pale. I noticed his Gills are a bit reddish or purple and his fins are melting away(sidefins and the bottom of the tail). In fear he could get fungi on top of all this, i am medicating the whole tank with Ektozon aquarium salt and it seems to work for now.




I am totally clueless by now. I really need help. It seems something in the aquarium is killing off fish one by one and i can't really make out what it is. Water parameters where always fine, no ammonia, no nitrite (except very small spikes when a fish died).

The long Story:
It started off with a Kuhli loosing some of its tail. It seemed to be fine otherwise and i didnt know if it had its tail on purchase so i didn't bother.
After a while one of our Corydoras got bloated, his eyes popped a bit and he got a red belly. I had him separated in a 30L(7Gal) Quarantine Tank as soon as possible. I wasn't able to treat him, because i had no time at the moment. As i wanted to start some treatment a day later he was already dead.
The group seemed to suffer fromt he loss. They were orobably not big enough as a group, didn't swim as much together and hid more, so we purchased 2 more Corys. We kept them (the first fish that were introduced like that) in the Quarantine Tank for a week, to make sure that they wont bring new illnesses.
Sometime later when the 2 Corys already lived in the 100L i noticed small white blotches on one of the Corys (an older one i suppose, they are hard to distinguish). I noticed it pretty early i think. At first i thought he had just lost some of his colour on some areas of his left side. On further investigation i could see that it was a bit fuzzy. I supposed it was some fungi. I removed him imediatly and put him into the Quarantine Tank along with eSHa 2000 6 drops daily. I also put the same medication in a smaller dose into the 100L as precaution .
At first it seemed to get worse (both sides infected, larger blotches) and he went very lethargic. At one point i thought he died and i had to push him over with an Aquascaping Spatular till he snapped into existance again and swam away. I noticed in this time that the Kuhli with the shorter Tail also got Fuzz on the Tail so i put him along with the Cory and continued the treatment. The Kuhli died a day later. The Cory recoverd though and i put him back into the main tank as soon as the Blotches were gone (or only visible when looking veery closely) I continued treating the Main tank till last week when we went to our fish specialist for the Hatchets. We asked him about our situation and he gave us Ektozon aquarium salt. (I know the other stuff is probably bad for the corys because it got copper in it so i was glad to switch) Also i needed a treatment for scratching fish. this was going on for a long while now and it was just getting worse. Single fish were scratching and twitching once in a while. No matter what species, they were all doing it sometimes.

We got a Betta in the 7Gal now so i couldnt put the Hatchets in Quarantine. I treated their Bag water with the Aquarium Salt though and at the same time i put Salt into the Tank(4teaspoons solved in a bit of tankwater every other day)
The scratching had stopped from the first day. I am working fulltime now (still from home though) so i cant observe as closely as in the past but i havent seen a fish scratching once. One of the hatchets was ill before we got them and i think we shocked him to death. When we released them he sank onto the floor and squeezed into some bottom plants. He hung in there breathing heavily. I watched him (like an hour)till he stopped breathing and removed him.

3 days or so later i noticed another Hatchet having the same fuzzy tail the Kuhli had. In lack of a Quarantine Tank i took our biggest Aquarium Net, catched him(wich was easy because he was already lethargic) and hung it into the aquarium, so i can abserve him better, he wouldnt be as much in contact with the other fish and if he'd die i could just take him out. A 3rd Hatchetfish went missing too. I carefully moved some of the decor but couldnt find him anywhere. If he died all the scavengers wouldve eaten him up fast.
The Salt Treatment was continued and in my desperation i dropped eSHa 2000 on his Head. It took maybe 1 or 2 days till he died probably over night. I didnt notice at first because he was still floating on the surface. We had a minor Nitrite Spike after that, but not above 0.025.

Now this was half a week ago. And now the Cory is ill. His Symptoms seem like Ammonia Poisoning or something like that, but our Parameters are fine and the other Fish too. All the Corys are swimming happily with full fins, bright colors, clear eyes and shiny skins. They swim very occasionally to the surface for air, probably 2 times a day for the whole group. Except this one Cory. I don't know what to do. I tried separating him with the aquarium net, but he started lowkey panicking so i realeased him again. I dont know how or where i should treat him. And i dont know how i can stop this frequent illnessses... Should i continue Ektozone treatment? Or do nothing to reduce stress? Should i treat with the Copper stuff again?
Please help! *cries*

Tank

volume: 30Gal (100L)
running: 4months
filter: Juwel Bioflow Super
heater: no
temperature: 24-26C°
stocking of this tank:

• 2 otocinclus
• 1 Bristlenose Pleco
• 2 adult Sewellia lineolata (+ at least 15 fry, will be given away as soon as i can identify their gender)
• 4 Kuhli Loaches
• 7 Corydoras Julii
• 5 marbled Hatchetfish (small, added a Week ago)
• 3 Amano Shrimp
• 1000 Assassin Snails

I know its overstocked, the sewellia babies shouldnt be there and will be removed soon. I try to feed less to reduce waste and water quality seems to be good, probably because the tank is planted and we got a good cleaning crew. (nitrate is almost too low for the plants)

Maintenance
How often do you change the water?
every other week
How much of the water do you change?
depends...sometimes only 5L just for vacuuming the gravel, sometimes 20%
What do you use to treat your water?

• Easy-Life Ferro (iron for plants, but not very often)
• Nano Catappa Leaves once in a while
• eSHa 2000 (Medication to get rid of fungi, but we stopped Treatment last Week)
• Ektozon Aquarium Salt (since last week, still to get rid of eventual parasites, fungi, and scratching)

Do you vacuum the substrate or just the water?
in Waterchanges we focus on vacuuming the substrate on the areas not covered in plants (both sand and gravel)
We only change a small amount of water, because the Waterparameters seem not to demand a Waterchange per se.

*Parameters - Very Important
Did you cycle your tank before adding fish? YES and we only added small groups of fish at a time.
What do you use to test the water?

• Test Strips
• JBL Test Combi Set Plus Fe (+JBL PH 6-7,6, +JBL NH4)

What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.

Ammonia: 0
Nitrite: 0
Nitrate: 1-0,5
pH: 7 (a bit unstable 6,6-7,5)
GH: surprisingly high (13)


Feeding
How often do you feed your fish?
2times a say
How much do you feed your fish?
2 pinches (wafers will be broken so i can put small pieces in)
What brand of food do you feed your fish?
before Hatchetfish: Tetra Micro Granules/Tropical Mini Wafers Mix/JBL NovoFect Algae Wafer/as occasional Treat JBL Novo Artemio
with Hatchetfish: Nobrand Flakefood/Sera Bettagran/ Tetra Micro Granules/ as Treat Novo Artemio
i stopped especially feeding the algae eaters, they like the Micro Granules and should find enough Algae in the Tank by now. Also i think i overfed so i try to feed less.

Do you feed frozen or freeze-dried foods?
we got frozen food but almost never use it (havent since weeks)

Illness & Symptoms
How long have you had this fish?
He might be one of the 2 newer Corys (but i dont think so)
If he's from the older bunch, we got him since 3 months
How long ago did you first notice these symptoms?
I noticed yesterday or so
In a few words, can you explain the symptoms?
Lethargic, red gills, difficulty with balance and swimming, melting fins.
Have you started any treatment for the illness?
using aquarium salt (Ektozon °N) and more Catappa Leaves
Was your fish physically ill or injured upon purchase?
I dont know, but he might be the one i treated in the quarantine tank for fungi a while ago.
How has its behavior and appearance changed, if at all?
skin dull and greyish, lethargic, often surfaces for air.

 

I have a three spot Gourami displaying the same symptoms & like you my parameters are all good, I've treated with Seachem Paraguard & Kanaplex, it doesn't seem to be getting worse but no better either & it still eats when I feed. I'm at a loss as to what the problem is but I think I'll crank my QT tank up next week & put it in there to treat more aggressively if no change.

 

I'd test nitrates again with a different test kit. You can't have 1 nitrates

 

I'd test nitrates again with a different test kit. You can't have 1 nitrates

it's 1ppm why couldnt it be 1? the scale for the test reaches from <0,5 to 200 and 1-15 is marked as ok.

...I've treated with Seachem Paraguard & Kanaplex, it doesn't seem to be getting worse but no better either & it still eats when I feed...

Thanks for your reply,
Its hard to find medication that wont kill our snails and Shrimp. Paraguard and Kanaplex both will harm them
Yes the Cory eats just like your Gouramis. And sometimes he will try to swim with the group, but not for long... I just hope the others wont catch this illness...

I'd test nitrates again with a different test kit. You can't have 1 nitrates

aand i have to add, i tested the nitrate with different test kits and brought the water to our fish expert store where they tested it too.

 

I know you treating the tank but wouldn't it be better for the little guy in a smaller tank where he doesn't have to swim far to the surface and get stressed, if its possible

 

I know you treating the tank but wouldn't it be better for the little guy in a smaller tank where he doesn't have to swim far to the surface and get stressed, if its possible

Good point...
we only got the 7gal, and there is a Betta in it. It would be even more stressful. I have thought about putting him in a Saladbowl or something of that sort, but i am not sure if we got something thats large enough for the little guy...

 

I had the same problem with the pectoral fins rotting on a severum and never did find out the cause and they never repaired

 

First, if you have any concern about ammonia in your tank (even though the test is showing zero), you can always use zeolite or ammonia removal pads to remove any ammonia present, or you can add a chemical like Seachem Prime or API Ammo-Lock to bind the ammonia so it won't hurt your fish.

Can you have 1 ppm nitrate in your tank?. Sure. I have zero ammonia, zero nitrite, and zero nitrates in my heavily planted aquarium. I add nitrogen fertilizer to the tank on a daily basis and still cannot get any nitrogen readings. The plants consume the nitrogen shortly after I add it.

Do be careful when testing nitrates. It is easy to get a false low reading if you do not follow the kit instructions carefully. You have to shake up the reagents before you use them, You have to add the appropriate amount of reagent from bottle 1, shake up the sample container and wait until it has reacted. Finally, you have to add the second reagent and shake up the sample container and wait for the color to develop. If you shortchange any of the steps, you can get a low reading. Before I added plants to my tank, I did have nitrate readings, but no more.

Your fish ailments, however, might well be from a bacterial or fungal disease or parasites. If the entire fish population in the tank does not appear to be affected, remove the Corydoras to a quarantine tank for treatment.

Have you tested the carbonate hardness KH of your tank. Fish do not like pH swings. If your pH is changing from 6.6 - 7.5, the KH iin your tank may be too low. Typically, the KH and GH numbers should be similar. A GH of 13 is not super hard, but it is harder than many fish (including Corydoras) prefer.

Have you tested your water that you use for water changes. Although many people have suitable tap water for aquaria, many people do not. I currently live in an area where the tap water is unsuitable, so I have to use RO water to which I add minerals for use in the aquarium. If you have hard water and an ion exchange water softener, the softened water is high in sodium and a poor choice for aquariums.

Good luck in diagnosing and correcting your problem.

Sorry, I forgot one more thing. Corydoras are bottom feeders. They need foods that sink to the bottom. I believe you mentioned that you are no longer using algae wafers that sink. Corydoras will eat algae wafers, but the primary component of their diet should be inverterbrates. Foods such as sinking shrimp pellets are ideal for Corydoras. If your Corydoras are not getting sufficient food, the stress will make them susceptible to disease.

 

Sorry, I forgot one more thing. Corydoras are bottom feeders. They need foods that sink to the bottom. I believe you mentioned that you are no longer using algae wafers that sink. Corydoras will eat algae wafers, but the primary component of their diet should be inverterbrates. Foods such as sinking shrimp pellets are ideal for Corydoras. If your Corydoras are not getting sufficient food, the stress will make them susceptible to disease.

Thank you so much for the detailed answer!

I might follow your suggestion and put some Sera Toxivec in to get rid of eventual ammonia or nitrite.
As for the Nitrate Testing, the Test from JBL seems to be a bit easier than you describe, but i always follow the instructions and the fish store had it tested once too. Our tank is well planted so i think this is correct.
I tested the Tap Water, it's all fine, i put in water purifier nonetheless and mix it with destilled water for waterchanges. I use the destilled water also to fill up what evaporates. Before setting the Tank up we had the Tap Water tested at the store too. It was good with low phosphates, very low nitrate but high silicate.

Quarantine Tank: At the moment ther is only the 7gal with a Betta in it. Should i put the Cory for Quarantine in there anyways? I could move the Betta to the 30Gal in the meantime (in the big tank he is friendly to the other fish and too slow to get them, but in the small one he's a bit of a jerk). Or would it be ok for the Cory to live in a Saladbowl for a while?

KH is surprisingly low in comparison to the GH but it might be caused by the Oak Extract i used some weeks ago. (We had PH of 8 in the beginning and i tried to lower it with the oak extract. I removed a Stone that was appearently pushing PH up and could stop using the oak stuff.) Maybe it still affects the readings of KH?
How would i soften the water?

Edit: Feeding Corydoras: I had Algae Wafers and a Wafer Mix with Fleshy stuff and Veggie. I stopped both but they still got the Micro Granules from Tetra wich is also a mix of Fleshy, Shrimpy Stuff and Veggie. They granules float on Top a bit longer so the Hatchets can get them. There is still enough stuff that sinks to the bottom. Its the same with the Artemia and the Bettagran. I just wanted to stop feeding stuff that the Hatchets cant get to reduce waste and time.

I had the same problem with the pectoral fins rotting on a severum and never did find out the cause and they never repaired

Did they survive?

 

Sorry I can't help but do you literally have 1000 assassin snails?

 

Did they survive?

Although he died i don't think it was from the fin problem he'd been beaten up by an oscar i had him in a quarantine tank for 6months

 

Sorry I can't help but do you literally have 1000 assassin snails?

uum feels like a thousand. They might be around 30 and steadily producing

 

FabianFynn it was a severum that lived with my oscars for two years then developed the same fin melting as op I think thr Oscar became mature and aggressive

 

Sure

it's 1ppm why couldnt it be 1? the scale for the test reaches from <0,5 to 200 and 1-15 is marked as ok.



Thanks for your reply,
Its hard to find medication that wont kill our snails and Shrimp. Paraguard and Kanaplex both will harm them
Yes the Cory eats just like your Gouramis. And sometimes he will try to swim with the group, but not for long... I just hope the others wont catch this illness...



aand i have to add, i tested the nitrate with different test kits and brought the water to our fish expert store where they tested it too.

Sure thing boss

 

Sure
Sure thing boss

The API Nitrate test kit is commonly used in North America. It has color indicators for 0 ppm and 5 ppm. Thus, getting an accurate reading of 1ppm would be difficult. The JBL test kit is a different type of test and has a different color chart that includes a color swatch for 1 ppm. Thus, with that test kit, a reading of 1 ppm is quite reasonable.

Your response above to FabianFynn was not appropriate.