Important Neon Tetra Sick Or Injured


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The problem: One of my new neon tetras has some sort of gill issue.

What is the water volume of the tank? It's a 26-gallon bowfront tank.
How long has the tank been running? One month; cycled with year-old established filter, bottled bacteria, and seeded gravel.
Does it have a filter? Yes; it has a Top Fin Silenstream 30 gallon hang-on filter, as well as a Top Fin 30 gallon undergravel filter.
Does it have a heater? Yes; it's a 100W Submersible heater set at 77 degrees Fahrenheit.
What is the water temperature? The tank stays at around 80 degrees due to the two large windows in my room. Texas heat, you know?
What is the entire stocking of this tank? 8 cherry barbs, 8 neon tetras, 1 bristlenose pleco, 1 dwarf gourami. Some random pond snails also hitched a ride, but I remove all babies whenever I see them. I left in 1 adult, though.

How often do you change the water? Weekly, but sometimes I do them twice a week just to be sure.
How much of the water do you change? Not sure of the percentage, but I fill a 5-gallon bucket.
What do you use to treat your water? Top Fin Water Conditioner.
Do you vacuum the substrate or just the water? I vacuum as much substrate as I can until it runs clear, then vacuum up any floating debris. So I do both.

Did you cycle your tank before adding fish? Yes. I added ammonia through fish food until I had 0 ammonia, 0 nitrite, and presence of nitrate for at least a week straight without any spikes.
What do you use to test the water? API Freshwater Master Water Test Kit and API Test Strips 5 in 1.
What are your parameters?

Ammonia: 0 ppm
Nitrite: Somewhere between 0 and .25 ppm; today is water change day, just haven't done it yet.
Nitrate: 10 ppm
pH: 7.6

How often do you feed your fish? I feed them every day, excluding Sundays.
How much do you feed your fish? They get a pinch of flake food most days, and the pleco (and snail?) get a few algae wafer bits every other day. On Saturdays I give them cut up blood worms, and I give the pleco a full algae wafer or a small piece of cucumber, depending on what I have. I remove leftover food within about an hour on this day, and then every Sunday I do a water change without feeding them.
What brand of food do you feed your fish?
TetraMin Tropical Flakes, Top Fin Freeze-Dried Bloodworms, and Tetra Pro Preco Wafers.
Do you feed frozen or freeze-dried foods? Yes, the bloodworms are freeze-dried.

Illness & Symptoms:
How long have you had this fish? A week.
How long ago did you first notice these symptoms? Yesterday or maybe the day before.
In a few words, can you explain the symptoms? The fish looks as if its operculum on one side is torn away or something. The gills are visible on this single fish when they are not visible on any of the other fish in the tank.
Have you started any treatment for the illness? No. Don't know what it is.
Was your fish physically ill or injured upon purchase?
I didn't look very closely, so I'm not sure.
How has its behavior and appearance changed, if at all? It seems to breathe faster than the other fish and sometimes rests longer, but it follows its school diligently. It is still currently bright in color and active all throughout the tank.

Explain your emergency situation in detail: I noticed that one of my newer neon tetras seems to have a very bright red mark, which I realized were his gills on one side. My first thought was that the ammonia had spiked, but a test revealed that the levels were all normal. I did a water change anyway. Since I didn't get a good look at this fish before I put it in, I'm not sure if it's had this since I got it, or if it's a new thing. It only seems to be affecting this one neon tetra. Any ideas as to what it could be? I think he may also have something on his lip, but he won't stay still long enough for me to get a good look at his mouth. A picture of the affected fish is attached.



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HI and welcome to Fish Lore. Thank you for providing so much information, that definitely helps.

The exposed gills look quite healthy from what I can see, so I don't believe there's any disease at play here. My guess is either a birth defect or an injury, albeit not a recent injury. Fish can function okay with such injuries, however, great care and precautions should be taken to insure that infection or further damage to the exposed gills does not occur.

It does seem that your parameters are good (sometimes it's hard to differentiate the colors of the test tubes), and your maintenance schedule seems pretty good. I would say a 5 gallon bucket would be roughly 15-20% changes weekly. If that is working to keep your parameters as you had listed above then keep at it. The extra water changes are a healthy habit, too, as an added sense of security in making sure the parameters stay in good quality.

A mild suggestion, one you do not necessarily need to take, would be to replace the plastic plants with real ones or at least with the artificial silk plants. This would help eliminate the chances of the fish accidentally poking its exposed gills on the ends of the plastic plants and risking damage. There are very easy low-demanding plants that are beginner friendly that can be suggested should you decide on taking that path.

Hopefully this helps, but please do feel free to ask as many questions as you'd like. The community here is a friendly and knowledgeable one.
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Thank you for the welcome, and it's no problem!

That's a relief to hear. I really care about my new fish despite only having them for a few days, haha; I didn't want to have to give him a burial at toilet. I thought that maybe it could be a birth defect, but I just wasn't experienced enough to say for sure.

I do have trouble differentiating between the colors, so that could be a mistake on my part. Thank you for the percentage! I'll write that down somewhere. And yeah, I actually enjoy the water changes. Gives me something to do, haha.

I do want to replace the plants with real plants, but unfortunately these fish seem to have some sort of vendetta against them! A few of these fish used to be kept in another tank for a school project (with live plants), but the pleco and the snail absolutely obliterated them within just a few weeks. Even the gouramI was picking at them, and eventually they just died and rotted. I've tried to keep more plants alive but to no avail, even when giving the bottomfeeders more to munch on throughout the day, so I just gave up and got plastic ones for their new tank since we didn't want to deal with buying more (since to get more plants, it would be an hour long drive to the nearest pet store). As an alternative I did try to to look through all my local pet stores for silk plants, but sadly I couldn't find any big or nice looking ones for a tall aquarium. I do want them, however, since I'd like more plant movement in the tank. Maybe I can try to order some online.

Thank you so much for your help. If I can ask, I do have one more concern, namely for my pond snail; its shell seems to be turning white. I'm not sure if this was always the case with its coloring, since I have a bad memory, but I was pretty sure it used to be brown! I read online that this might be a calcium deficiency, but my water is already pretty hard. Do you think I should add in some calcium somehow, or just leave it how it is? It's definitely still cruising the tank, so I don't know if I should bother worrying.

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