Nora Loves Corys

I'm sure it is in response to the irresponsible and unwarranted use of antibiotics in the aquarium hobby. When you don't use things responsibly and judiciously, they get taken away. This is happening on a smaller scale in the US: https://www.fda.gov/news-events/press-announcements/fda-warns-nine-manufacturers-distributors-unapproved-antimicrobials-animals

So the KH testing from 0-50 is actually not that big a difference (since the API test kit is measuring either 0 or 50 when it is very low--it could be anywhere in between those two values, the test is very granular)--no matter what, 50 is very low, and I suspect this is part of your problem. Note your pH is under 7 as well, likely due to the loss of buffering capacity from the low alkalinity. Definitely consider some action to increase your alkalinity given that your 50% water changes (usually big water changes like that replenish alkalinity) aren't working. The UV filter is separate from the alkalinity problem. This is to reduce bacterial load in the tank in case something like mycobacteriosis is going on (here's a more detailed discussion that touches on the UV filter: https://fishkeepandchill.com/conversations/f/mycobacteriosis-the-ubiquitous-scourge-of-the-aquarist. Also, HOLY SNAIL!

I'm glad it went okay, euthanizing fish is so sad. Hazarding a guess, it was probably not anything good--mycobacteriosis, some kind of virus, etc. You can submit fish for necropsy and diagnostic testing, but it's expensive so people rarely do.

I'm very sorry to hear about your fish. If it is helpful, here is some high-quality information about euthanasia: https://fishkeepandchill.com/conversations/f/euthanasia-for-aquarium-fish-when-should-it-be-done-and-how

I'm sorry to hear that.

In your previous post, what are you defining as a "substantial water change"? I think there actually may be an old tank situation going on here. Alkalinity = KH. It is the carbonate and bicarbonate. They act both as buffers to prevent large pH swings, and as a carbon source that the beneficial bacteria in your biofilter require to convert ammonia into nitrite into nitrate. More information here:

I don't think you necessarily have "Old Tank Syndrome" if your water is coming out of your tap with low alkalinity; however, I think it's low enough to try to increase (which you have been trying). @Jen Loves Bettas would be better than me to speak about the best way to add alkalinity to your tank. She also would have suggestions about a UV filter, I wonder if that might help your situation. How many fish are in there (it sounds like a lot)?

Sorry to hear about your fish. A few thoughts: > You can use this locator to look up fish vets near you: https://fishvets.org/find-a-fish-vet/ > How frequently do you perform water changes on your tank, and how much? Your alkalinity (KH) is very low; this is what feeds the beneficial bacteria in your biofilter that convert ammonia into nitrite and then nitrate. > How long has this aquarium been running? I am wondering if you might be dealing with more of a chronic, "old tank" disease such as mycobacteriosis (which I believe GloFish get pretty frequently): https://fishkeepandchill.com/mycobacteria

Sorry to see that your fish is not doing well. In general, when a fish gets dropsy (and it looks like he has fluid in his coelom that is creating his "wideness" as well as pineconing scales), it is time to start considering how his quality of life is. This resource written by a fish veterinarian and professional aquarist about euthanasia (when it is time, and how) may be helpful for you to read: https://fishkeepandchill.com/conversations/f/euthanasia-for-aquarium-fish-when-should-it-be-done-and-how He is a lucky fish to have you as such an attentive and caring owner. Best wishes to you and your fish.

Very hard to say what it is from this picture, but fish losing their ability to maintain neutral buoyancy in the water column and control their swimming is usually a sign they are terminally ill. Here is a resource written by two experts about euthanizing aquarium fish, if you feel that your fish's quality of life continues to decline: https://fishkeepandchill.com/conversations/f/euthanasia-for-aquarium-fish-when-should-it-be-done-and-how Best wishes for you and your fish.

I don't use Prime, so I can't comment intelligently on this. I'm sorry!

The test strips (and even the liquid test kits) have low sensitivity for water quality parameters; this means that even if everything reads "normal" with them, you still might have a water quality problem. This is particularly true for nitrite, which is toxic at levels as low as 0.1 ppm; from casual perusal I believe neither the liquid test kits nor strips detect nitrites until they have accumulated to 2.5X this level. It is never wrong to do a large water change (making sure that the new water matches the water parameters of the tank water) to make sure the water quality is pristine--whatever is wrong with your fish, this can only help them.

Sorry to hear about your betta fish--they have such unique personalities, it is always sad when you lose them. They are definitely a species of fish that can be plagued with mycobacteria. There are two nice articles here, both of which mention mycobacteria and UV filters: > Dos/Donts for Fighting Mycobacteriosis > A more in-depth discussion I am not aware of any high-quality studies looking at how UV filtration on a hobbyist-sized aquarium helps with controlling mycobacteriosis. But anecdotally, I think it helps. I would not worry about it causing problems with bacteria in your biofilter; the bulk of these bacteria live in your filter on the media specially designed for them to colonize, and they are not just drifting around in the water column (which is what the UV sterilization is working on). Also, many commercial aquaculture operations use UV filtration on recirculating systems with no effect on biofiltration. Hopefully this helps, and good luck with your community tanks. 🐟😎

It is hard to know what is causing that pale area near your fish's tail, but I agree that it looks suspicious. The most important thing you can do when fish have compromised skin (whether from injuries or something else) is to keep the water quality pristine and maintain excellent hygiene in your tank. This includes keeping the ammonia and nitrites at zero. Large water changes (50%+, but making sure that the temperature and general parameters of the new water are the the same as the water in the aquarium) help keep the water free of bacteria and other pathogens that can cause a secondary infection on the compromised skin; clean water is almost like a clean Band-Aid protecting the fish's skin. I hope your fish improves!

"Swim bladder issues" is a layman's term that people often use when a fish is not able to maintain neutral buoyancy (it is floating up to the top or it is sinking to the bottom) and sometimes is also used if a fish is swimming sideways or spiraling. All of these problems may or may not be caused by problems with a fish's swim bladder (i.e. disease processes completely unrelated to the swim bladder can also cause all of the problems I just listed). The swim bladder is an organ that fish can add and remove gas from to adjust their buoyancy in the water column. It is a very delicate organ with extensive blood vessels that help with gas exchange--this means that it can be easily affected by all sorts of disease processes in fish, especially inflammation caused by infections (bacterial, viral, fungal). It is hard to know if the problem with your Ember Tetra was related to its swim bladder or not. Many times when fish are very ill, they struggle to swim, and this is more due to how weak and lethargic they are than any failure by the swim bladder. Here is a resource written by an expert with accurate information about swim bladder disorders: https://cafishvet.com/fish-health-disease/swim-bladder-disease/