GloFish and Ich

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Aquarium Advice Newbie
Mar 23, 2023
Thompson's Station, TN
HELP! 10G tank, 5 GloDanios, and 5 GloTetras (I realize that's pushing it for a 10G so feel free to lecture me :facepalm: ) My Glotank was my "golden child" tank: Perfect cycled water before adding fish, added fish 3 (and one group of 4) at a time over the course of a month and a half, they all loved each other and schooled and played, no water parameter issues, no concerning behavior, no issues. I started noticing same-species aggression (Tetras to Tetras / Danios to Danios) a few days ago and noticed ONE green Tetra had fin damage. When looking up causes/treatments, I came across ich descriptions and then noticed possible white spots on the green one. Could be a "google paranoia" issue :lol:. Now I can see white dots on a few of them.
Question 1: Sometimes the spots look like actual white spots, and sometimes they look like glistening/silvery scales. Does ich sometimes get overlooked/misdiagnosed because of this? Or should the white spots be SUPER obvious no matter the angle, direction, lighting, etc? Don't want to treat for something I don't need to.
Question 2: IF it is ich, I want to go the heat/salt route first to avoid medications. I will increase my temp by 1-2 degrees every couple hours until I reach 86 Fahrenheit. I will also do a small water change to add a gallon of conditioned water + salt (3 tblsp). I have plants in the tank but will move them to another tank during this process. Can danios and tetras handle water temps at 86F or higher? Everything just tells me what they typically need. And danios typically need 65-77 and tetras 75-81F (to be specific - this is what I have read for Glo Danios and Tetras). I know 88-90 is ideal for treating ich but I am even nervous to move it up to 86 for these fish. And I know 86F is the minimum for treating ich.
Question 3: If the fin damage doesn't improve with the ich treatment, should I do a round of fin rot treatment after I have completed the heat/salt ich treatment (as in - completed all necessary water changes to remove salt)?
I am sort of a newbie at this. I have 3 tanks and do A LOT of research and really consider my fish part of my family as most feel about their dogs. In my heart, I know the aggression is leading to the issues and the aggression is probably because they are overcrowded. My husband will probably stick me on the side of the road if I get a bigger tank and I don't want to remove any if I don't have to. I am willing to take out decorations to provide them more space if it's an overstock issue but then I read they need more places to hide if there is fin nipping. Sorry for the long post. THANK YOU for any help you can provide! :fish2:
Basic first aid for fish.

Test the water for ammonia, nitrite, nitrate and pH. Post the results in numbers here.

Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.

Do a 75% water change and gravel clean the substrate every day for a week or until the problem is identified. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so any medication (if needed) will work more effectively on the fish.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.

Post clear pictures of the fish so we can check them for diseases.

Provide some information on things like how long the tank has been set up for, how long have had the fish, if you added anything in the last 2 weeks, filter and tank cleaning, etc.


You can treat white spot by raising the water temperature to 86F, it doesn't need to be higher. You do a huge (80-90%) water change and complete gravel clean before raising the temperature. This reduces the number of parasites in the tank so there are fewer to infect the fish. Clean the filter too. Increase aeration/ surface turbulence any time you raise the temperature or use chemicals in the tank.
Additional Info

Thank you so much, Colin_T!! I am adding pictures to this thread but I added more pics to my GloFish "album" on my profile of individual fish.

I JUST tested the water and will post the pics here. All I have are the test strips and I know they aren't the BEST method but it's all I've got right now. The nitrites are definitely high. Probably at a 2.0ppm The hardness is also in the "hard" range. The ammonia, nitrates, and Ph look to be in the normal/appropriate range The filter may be coming up on six weeks old at this point. Last time I changed it, I used it to cycle a new tank. I did a 75% water change this past Saturday (a week ago tomorrow) because I had been out of town and it needed it. I added an airstone and low-light plants when I noticed them swimming primarily at the top of the water and getting aggressive. I run the aerator 24/7 because they seem calmer and enjoy it being on.

Tank established: ~4 months
Lost the first 4 Danios but all have survived since so last time fish were added was probably ~3 months ago. Never had any issues with water parameters or behavior prior to noticing the fin damage early this week. Could have happened while I was out of town last week. I track all my water changes and parameters on a spreadsheet. Didn't start that though till I had 3 tanks going and started getting overwhelmed with keeping it all straight. The nitrites and ammonia were really high before the 75% water change I did last weekend but I thought the water change would have helped for longer than a week.
Full disclosure: self-diagnosed overthinker and perfectionist here. I (*have been told*) probably stress over my tank water TOO much and try TOO hard to keep them all perfect.

Water change, filter, cleaning question: Should filter changes and water changes happen NOT at the same time? In other words, I get nervous because I know the filter holds the good bacteria the tank needs and when you do water changes, you remove the good bacteria. So you need to keep an old filter media in to give the new water the good bacteria and then you can change the filter when the water is "cycled" again, correct? I read too much on the internet and get overwhelmed and confused. That's why I decided to join this forum cause after reading certain things, I still have questions that I can't find answers to. :(

Thank you so so much for all your help!


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I can't tell if they have spots, the images are too small and my eyesight isn't very good these days. White spot looks like small grains of salt sprinkled over the fish. These white dots disappear after a few days and reappear in numbers a few days after they disappear. If the white dots have stayed the same for a week or more, then it isn't white spot.

White marks on the fish can be excess mucous caused by something in the water irritating the fish. Ammonia, nitrite or high nitrate readings can cause excess mucous. Cleaning up tank conditions (big daily water changes and gravel cleaning the substrate) usually fix excess mucous problems.


The damage to the tail looks like bites from other fish. Black widow tetras (aka skirt tetras) are renown fin nippers and you have a combination of long and short fin tetras. The short fin fish are probably biting the long fins. This problem is made worse by low numbers of tetras. These fish naturally occur in groups consisting of thousands of individuals and when you only have 3 or 4 in a tank, they stress out and become more aggressive. However, the size of the tank will limit how many fish you can keep. As a general rule, tetras and danios should be kept in groups of at least 10 of their own kind, and more is better.

Clean water should allow the fins to heal by themself. You can add salt to help reduce the risk of infection but they don't normally need it unless the damage is significant, but it doesn't look infected so I wouldn't use salt at this stage. I have included directions for salt at the end but you don't need to add it unless the damaged fins get white fluff/ hair like growths on them, this is Saprolegnia fungus. Or if the fins start to get red edges or red lines in them, then add salt.

Most tetras also come from black water (water that is stained with tannins and looks like tea). Your aquarium is bright and has no floating plants. This will add to the stress the fish are under. You can either add some floating plants like Water Sprite or Red Root floaters, or reduce the light above the tank. You don't appear to have any live plants in the tank so you only need the light on for a few hours in the evening so you can see the fish. The fish can see each other in quite low light and don't need the light above the tank. If you can dim the light (reduce the brightness) that would help, otherwise move the light unit to one side of the tank so the other side isn't as bright.

You should put a picture on the back of the tank to help the fish feel more secure. You can buy aquarium backings from pet shops or online. You can also use coloured card or a plastic bin liner. Just tape them to the outside on the back of the tank. A black backing would make the ornaments and fish stand out much more than they do currently.


You need to get the nitrites down to 0ppm. The easiest way to do this is with big (75%) daily water changes and gravel cleaning the substrate.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

You mention changing the filter about 6 weeks ago. Do you actually replace the filter media/ materials regularly or do you just clean them and re-use them?

How often and how do you normally clean the filter?

If you replace the filter media, you remove the good bacteria that keeps the ammonia and nitrite at 0ppm and you get ammonia and nitrite readings that can harm or kill the fish. Filter media should be squeezed out in a bucket of aquarium and the media is re-used. The bucket of dirty water gets poured on the lawn outside.


You can add rock salt (often sold as aquarium salt), swimming pool salt, or any non iodised salt (sodium chloride) to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres (5 gallons) of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres (5 gallons).

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria, fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

When you first add salt, add the salt to a small bucket of tank water and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.
Wow! Thank you so so much!! I will start the daily water changes today and keep an eye on the fin damage. If it gets worse, I will follow your salt directions.

I added a few live plants in the tank and a few floating anacharis the other day. Before I added the plants, I didn't turn on the bright light ever. Only the black light. Now that I have added some plants, I try to keep the bright light on for 6-8 hours for the plants (they are all low-light plants). Good to know the bright light is not their favorite and to keep it on only when absolutely necessary for the plants.

Thank you again so much for your thorough and helpful responses! I appreciate it! (And so do the fish!)
Black lights are normally Ultra Violet (UV) light and this isn't good for fish from blackwater. These fish aren't normally exposed to high levels of UV light. If you have albino fish in the tank, they can get skin cancer from UV light.
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