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White Cloud minnows have been ill for a while; unsure what to do.


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I usually post on Reddit, but I've already made a number of posts and figured it would be better to branch out. Sorry in advance for the very long post ahead.

I currently have ten White Cloud minnows (Tanichthys albonubes) inhabiting a 10 gallon planted aquarium. At one point there were 15, but two died of potentially related causes, and one was fatally injured by accident. They live with N. davidi shrimp and three species of snail. The tank has been up and running since the end of June.

My prime suspect for the "mystery illness" afflicting them is streptococcosis, but only based on clinical signs. I know that gram-positive bacterial infections are rare in fish. I also can't confirm this, because I would need to have someone conduct a necropsy, and for them to find gram-positive micrococci in the brain & kidneys. The fish seem too small and decay too quickly for proper examination in this manner, not to mention I don't have the resources available to me.

In case it can mess with water parameters, I'll mention that I started dosing the tank with API E.M. Erythromycin on January 6 (today is day 3). 


pH ~7.8, higher than expected. 

Nitrates 0ppm

Nitrite 0ppm

Ammonia 0-0.25ppm. Using API test kit, and the reading is very consistent.

Temperature 69.4°F / 20.8°C

Hardness and KH unknown, sorry. Guessing hardness is okay, since the shrimp always molt well.


Two of my fish out of 12 (after the three deaths mentioned) were sicker than the rest, so I put them in a 2 gallon tank I had as a spare. One, an adult female, had a number of symptoms, listed below. The other, a juvenile female, was in slightly better condition (at the time I wrote the adult's symptoms, Dec. 27. Eventually she declined to the same level, minus the buoyancy issues and lymphocystis).

The first I had to euthanize, as her condition was so severe and I was about to leave them for five days, in which time she would likely pass on her own. I had to put the second back into the main tank due to ammonia issues, and I could no longer find her a couple days later. I assume she was scavenged by my snails and shrimp.

Symptoms included:

- During the last few days of life (Dec. 24-27), tendency to get pulled towards the filter. It's a very gentle filter, and I put a pre-filter sponge over it so she couldn't get sucked in, but she tended to get stuck behind it and stayed plastered there between the intake and the back wall of the tank.

- Development of lumpy, fleshy protrusions. First one noticed on Dec. 22; had developed overnight, only one on her head, left side. Within a day she had bumps on both sides; some had spread into patches (a couple millimeters long, I believe). Looked like lymphocystis.

- Very lethargic. Occasionally would move around, but only when disturbed; sometimes did not react to disturbances, especially within ~1 hour of lights going on. Normally at the bottom of the tank or against the filter, but sometimes attempted to swim when she had more energy. 

- Could not eat. For maybe a day and a half she'd peck at floating objects and plant tips, but would not show interest in fish food. She had made some efforts to eat, but spat food up.

- Did not poop for at least one and a half weeks (~mid-Decenber to Dec. 27, day of death).

- Heavy breathing. The worst of it started Dec. 24 and was ongoing at time of death. She never piped at the surface, but flared her gills out pretty widely and breathed through the mouth. From Dec. 25-27, her breathing had slowed quite a bit.

- Tattered, shrunken fins, which didn't improve.

- Noticeable tilt. Her body was both tilted forward and to her right side. When swimming she spun somewhat.

- Left side of body showed noticeable deformity. Left side of the head, underneath the mouth and towards the gill opening, was swollen. I caught a glimpse of her while swimming and saw that her left side appeared almost indented, like there's a big divot in it. Her belly was somewhat bumpy. The juvenile fish was also showing asymmetry on the same side.

- Had negative buoyancy; slowly sank downwards unless actively trying to move up. When in an epsom salt bath, she floated to the surface. Her buoyancy on Dec. 27 was undetermined, because she was usually up against the filter.

- Somewhat bloated; most evident when looking at her from the gills forwards, as the head appeared too large. There was a noticeable bump on the top of her head as well.

- Bilateral exophthalmia (popeye, both eyes). Has gotten better over the last several days after removing her from the main tank, but not by much.

- Scales began pineconing. About a week before (Dec. 20-ish) I couldn't even tell if she was pineconing, but as of Dec. 24 some of her scales were visibly pulling away from the body. Pineconing only worsened.

- Body was curved most of the time, particularly when at rest. Tail usually curved up, sometimes in a mild "C" shape when at rest, but usually to one side or the other. Tail hung slightly down on day of death. 


There are now two obviously sick fish in the tank, both male, one adult and one subadult. The subadult has been sick for longer, and had started showing symptoms a day before my adult female was euthanized. He stays away from the group of fish most of the time; usually hangs at the bottom of the tank. Head looks swollen all around. Eyes seem relatively okay, but I think they protrude a little. He is lethargic, not eating (he tries, but spits out all food); there is a little divot where his gills meet the rest of the body, since he hasn't eaten in a while. Where his pectoral fins meet the body, there is red discoloration under the scales, sort of like blood spots. His body is darker than usual for this fish. Pictures below.


The other fish, an adult male (named Chad because he was the first to spawn with a female), is showing a partially swollen head as well. He is lethargic, but only as of today. He is also separating from the group, though he comes out at feeding time after a minute or so. His belly occasionally looks "pointed;" maybe you'll see in the second photo of him. He still eats, still looks comparatively healthy, but I'm sure his condition will change. Pictures below.


I began dosing erythromycin in the water as stated at the beginning, but I am unsure if it's working, or if it will work at all. I have tried API GenCure as well in the past, to seemingly no effect. Because of my inexperience, lack of money and tendency to worry myself to extremes, a long time has been spent agonizing over my aquarium's problems. I still have a feeling I'm not going about this correctly, but have next to no idea how I would fix this problem. 

Hopefully the information given is helpful. Thank you for reading, and sorry this post is so incredibly lengthy; I don't want to leave anything out.

Edited by cinnanoodles
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With the symptoms your describing it could be a viral or bacterial infection what I would do is a more broad spectrum antibiotic treatment kanaplex and Jungle fungus clear fizz tab's containing nitrofurazone following this treatment plan it more effective treatment for more severe bacterial infection 


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How old is this tank, and did something happen recently to the filtration? Swap sponges, December deep cleaning or something? An established aquarium should have zero ammonnia and a measurable level of nitrates. The medication may have contributed to an archaea die off slowing down ammonia conversion to nitrite. The zero nitrates reading to me indicates this is either a new tank or the biological filtration crashed several weeks before the measurement. 

My experience is limited, but I have observed ammonia levels leading to swim stability issues. I have a common goldfish who swam upside down wherever the current took him until I realized I needed to check for ammonia. Spent precious time feeding him shelled peas and other treatments for swim bladder issues. 

Some water conditioners will detoxify ammonia as well as removing chlorine/chloramine. I understand the budget issues, hopefully this is something you can afford. 

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On 1/10/2023 at 5:57 PM, cinnanoodles said:

@Colu Thank you so much. It seems like a long, systemic bacterial infection so far.

Are kanaplex and the fizz tabs safe for invertebrates? Been losing a lot of shrimp lately (seemingly also an infection, not sure what it is).

Kanaplex can effect shrimp causing them to slow down what you could do is a course of kanaplex in food feeding a small amount twice a day for 7 days while treating the tank with jungle fungus clear fizz tab's kanaplex is less likely to harm to your shrimp when added to food


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@Darax Sorry for the late reply. Thanks for your advice as well. I believe the erythromycin I dosed has affected the ammonia reading; I found a number of studies showing that nitrifying bacteria were either killed by erythromycin, or their ability to oxidize nitrogenous wastes slowed down. Hopefully that'll be resolved, since those studies also stated that the more resistant beneficial bacteria will grow and no longer be affected by erythromycin, even in higher doses.

Not sure about the nitrates (they worried me, too), but every time I test the tank, nitrates are at 0. The aquarium is about 6 months old now. I think the plants have something to do with it, but it could be an indicator of problems.

I'll keep looking at my test for signs of ammonia issues. A similar thing is happening with the ammonia test where it always comes up between 0 and 0.25ppm. Some have said that the API test always gives that reading even if ammonia is actually at 0, but I don't want to assume anything. Also, thanks for the insight on swim bladder issues - maybe my Top Fin water conditioner isn't quite right?

@Colu Thanks again, as well as for the recipe. I'll try adding Kanaplex to the fish food, but I have a feeling I'll need to dose it in the tank regardless, because the most affected fish aren't eating. Not looking forward to my shrimp slowing down, but if it knocks out this infection, I'll take it. Hopefully it doesn't kill them. 

edit - Would salt dips for the most affected of my fish help? I've noticed that this infection gives some of them popeye after a while, and I'm starting to notice it again.

Edited by cinnanoodles
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