Horror sights in the quarantine tank. What is this? The fish is still very active, eating, etc

[client]

The other side is fine.

 

[mattgirl]

Welcome to Fishlore

What are this fishes tank mates? Almost looks like something a pleco could do if it latched onto this fish with its sucker mouth.

 

[client]

Hey, thanks for the response. Last year I bought some black skirt tetra. One of them, the smallest male, had a central not too large, not small black dot on a side. Weeks later when he got bigger I could see that that's not just a black spot. It had big cracks. It died showing bones.

One year later, the smallest male black skirt tetra developed a... black spot on a side. It grew to this size. Is columnaris really black in black widow tetras? I use Easy Life Filter Medium. I tried to do some overdose of it. The QT tank is bare bottom, has 60 litres and in there - 10 black skirt tetras, with lots of filters, skimmers. pumps with strong venturi sucking in barely visible micro bubbles of air and the water. Filter media: sponges and nylon based wool in large amounts.
some black skirt tetra = 11
Tank
What is the water volume of the tank? >60 litres
How long has the tank been running? >2 years
Does it have a filter? Yes
Does it have a heater? Yes, but doesn't need any. It has a lid and because of it, I can't change the temp.
What is the water temperature? 28C-30C
What is the entire stocking of this tank? 10 black skirt tetra

Maintenance
How often do you change the water? Every day
How much of the water do you change? 15-20%
What do you use to treat your water? Easy Life Filter Medium
https://www.easylife.eu/products/fr...ter-medium/easy-life-filter-medium-activities
Easy-Life Filter Medium technical data - Easy-Life
Do you vacuum the substrate or just the water? I siphon the tank on bottom and bottom part of the sides. Is a bare bottom QT tank. I bought the fish last year and they never left the QT. I believe they still need time to prove me they are fine. Until then - under observation.

*Parameters - Very Important
Did you cycle your tank before adding fish? Yes
What do you use to test the water? I never test aquarium water
I store tapwater over 24 hours
Tapwater has these specs:

Feeding
How often do you feed your fish? Once a day
How much do you feed your fish? maximum: fingerprint stuck tetramin flakes and 20 tetra granules; I wait for them to eat all in 5-10 mins, usually all the food disappears in seconds, then I turn back on the surface skimmers and most of the pumps.
What brand of food do you feed your fish?
TetraMin® Tropical Flakes | Tetra®
Do you feed frozen or freeze-dried foods?
No
Illness & Symptoms
How long have you had this fish? One year
How long ago did you first notice these symptoms? There was a spot on one fish, I noticed it while holding the bag to look up, in the store, when they gave it to me.
No symptoms

Have you started any treatment for the illness?
No because I do not know the issue. I just use the product I use all the time, except now I don't do weekly dosage, now I do it daily, 10ml / day - no dose in the weekend
I'll stop and revert back to weekly if no sign of improvement. regular dose is 10ml per 30 litres weekly - it can be triple if one wants to cure.

Was your fish physically ill or injured upon purchase?
Yes, I think it's not normal - that spot. Never seen something like it. Hence - me posting here.

 

[mattgirl]

I am going to tag our resident fish disease guru A201 for something like this. Hopefully he will be able to help you out.

 

[LHAquatics]

Do you have a CAE

 

[client]

No, I never kept nor bought CAE. The fishes were supposed to be for the office, at work. Almost everyone working there was supposed to be able to keep these alive. So I went for single species - and hardy, beginner friendly. Cheap, irresponsibly bred, easy to come by - fishes, come with, more often than not, issues, it seems.

 

[mattgirl]

Can you share a photo of this tank with us? I am just wondering if the fish are comfortable with the amount of water movement in the tank. I know my long finned black skirts spend the majority of their time in the area of the tank between the 2 HOB filters out of the flow of water and an area with lots of live plants. BTW: They have been with me since Dec. 2015

I am wondering if whatever this is is worsened if these little guys are stressed out. Quite often stress can cause issues to come out that are normally dormant. I have to wonder if the stress the one little guy in the bag had gone through getting from breeder and finally to you was just more than it could take. If these fish aren't comfortable in their home I have to wonder if that could be causing what is happening. I am probably way off base with my thoughts but is it possible.

 

[DebClem]

Does the spot have any fungus around it like white fluffy looking? I would do a major antibiotic treatment on this tank it looks like a bacterial infection that is basically eating the fish. I am curious why when you seen the spot on the fish in the store you didn't just say hey this fish is sick I can not purchase this lot. Most likely it is something that was in the store aquarium that you have brought home with you. It could also be a parasite so to be safe I would treat for that also. I really can't tell by this picture

 

[A201]

Looks like a bacterial ulcer. My guess "Mycobacterium".

 

[Cherryshrimp420]

This is a bare bottom quarantine tank? A year is a bit too long to keep fish in these conditions....even with a filter. Their health will only deteriorate over time