Bubble and Red/White Growth on Glofish Fins

[Kinz]

My pink glofish tetra has developed this weird bulb on their fin not too long ago, and from looking it up and testing my tank (PH, Ammonia, Nitrate, and Nitrite, which all came out normal/nonexistent — I’ve had this tank for a few years now), I assumed it was too much oxygen. I had been letting my filter bubble so oxygen would get to the bottom feeders (tank is tall rather than wide) but lately my plants have kinda taken off…

I thought it was getting better after I raised the water level to stop the bubbling, but the base of this bulb on their fin started getting white growth — which again, I wasn’t too worried about. I’ve asked about that before and was told that was pretty normal, and they get it a lot. It’s never been like an infection or anything, just scar tissue or calcium deposits. All in all, only my long finned fish (all glo tetras) ever had an issue and it never spread or got worse/super concerning. Obviously I still keep an eye on it when I see it, but so far, it’s always consistently disappeared after a week or so.

This time, though, I was looking at the pink tetra the other day, and noticed little red specks within that white build up, and that’s when alarm bells started going off. I put them in a small tank I had handy with the same water and a heater, and have been watching my other fish like a hawk, alongside the injured one. Now I’m looking at the pink one today, and the injury(?) just looks a lot worse. I’m not really sure what’s happening, if it’s a tumor, or hopefully something I can treat? So far I’ve just been using Stress Coat and Pimafix in both tanks cuz it’s all I have...

It’s been a few days, and no other fish shows signs of this issue. Google has given me nothing, so any advice would be appreciated! I am going to bed right now, so if I don’t reply for a while I promise I’ll swoop around soon.
(I tried taking the best pics I could, the fish is a little jumpy…)

 

[Colin_T]

Oxygen levels have nothing to do with this or any disease. Low oxygen levels can cause the fish to suffocate but that's about it. High oxygen levels are good for fish.

It's a bit hard to tell what it is due to the pictures not being in focus. Digital cameras have issues with things like fish fins and white objects. But the red is blood and it appears to have an infection in the fin. You can try salt but if there's no improvement after a few days you will probably need a broad spectrum medication that treats bacteria and fungus.

If it's a tumour then there's no cure and you euthanise the fish when it can't swim or eat properly. However, tumours in the fins are uncommon.

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Before you treat the fish, do the following.

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. The water change 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 because salt and medications reduce the oxygen level in the water.

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SALT
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.

Keep the salt level like this for 1 to 2 weeks. If there's no improvement after a few days with salt you will need to try a broad spectrum medication.

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 (2 litres or 1/2 gallon) 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.

 

[Kinz]

Oxygen levels have nothing to do with this or any disease. Low oxygen levels can cause the fish to suffocate but that's about it. High oxygen levels are good for fish.

It's a bit hard to tell what it is due to the pictures not being in focus. Digital cameras have issues with things like fish fins and white objects. But the red is blood and it appears to have an infection in the fin. You can try salt but if there's no improvement after a few days you will probably need a broad spectrum medication that treats bacteria and fungus.

If it's a tumour then there's no cure and you euthanise the fish when it can't swim or eat properly. However, tumours in the fins are uncommon.

---------------------

Before you treat the fish, do the following.

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. The water change 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 because salt and medications reduce the oxygen level in the water.

---------------------

SALT
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.

Keep the salt level like this for 1 to 2 weeks. If there's no improvement after a few days with salt you will need to try a broad spectrum medication.

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 (2 litres or 1/2 gallon) 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.

Thank you so much for the information! I was definitely planning on cleaning the big tank as soon as I could, but I’ll do it a lot more thoroughly for sure per your instructions.

I totally forgot salt was a thing! I can definitely add that to the quarantine tank now. I hesitate to add it to the main one though because I do have corydoras in there and they have more sensitive scales, right?

And sorry for the crappy pictures, it was past midnight and I had horrible lighting alongside the usual camera focus issues haha. It’s basically a weird, semi transparent bubble in the fin with the white growth on the base. I might have gotten a better pic this morning attached here, but it’s still pretty hard to see details. I had read somewhere that gasses or high oxygen could lead to bubble growths, so that’s where I got that idea.

Do you have a recommendation for a broad spectrum medication? I’ve only really dealt with the API stress coat, pimafix, and melafix before. Not really sure what’s good out there.

Thank you again! I really appreciate the detailed response!

 

[Colin_T]

You can add salt to Corydoras tanks as long as you stay within the guidelines and don't use it for more than 4 weeks. In this case if we are talking 1 to 2 weeks. However, if you have a quarantine tank, then put the fish in that to treat for a week or two and then move it back into the main tank.

Medication wise maybe Waterlife Myxazin or Protozin will work better than Pimafix, Melafix and Stresscoat.

 

[AdoraBelle Dearheart]

It is hard to see from the photos - if you could raise the background blanket thing or use some dark background of some kind behind the fish, it'll be easier to get a clear photo of the fins and the fishe's general body condition. Take dozen's of photos, aim to get some in focus, delete the fails and upload the decent ones. Fish photography isn't easy, I know! But remember we cannot see the fish, tank, water conditions- anything! Except what you can share with us.

Diagnosis is difficult at the best of times when non of us are aquatic vets, but sadly this is the part of the hobby where we have to do what we can with the info we have.

Can I get some clarity about the history of this issue and the tank and it's stocking, please? I'm a bit confused! Did you say you've had this same issue crop up on multiple fish before? That is usually goes away within a week or two, but this time it hasn't on this one?

What's the tank size/dimensions and complete stocking, please? So tank length, height and width, not including stand and lid. Which species of fish, and how many of each?

It's not oxygen content. The fishe's general body condition makes me think it's an older fish, and possibly one that has been in a few battles, and may have been injured by another fish, rather than a disease or illness. Either way, putting it in a separate hospital tank was the right move!

When taking the pics, if you could get a shot of the whole tank, and any other fish that you have seen with symptoms like this before could also be useful info! Sorry to chirp in just to ask a bunch more questions rather than be able to be give a simple answer! But an aquarium is a complex little ecosystem in and of itself, and there are a myriad of things that can be happening, so the more info we can gather, the better the chances someone will be able to help!

 

[Kinz]

It is hard to see from the photos - if you could raise the background blanket thing or use some dark background of some kind behind the fish, it'll be easier to get a clear photo of the fins and the fishe's general body condition. Take dozen's of photos, aim to get some in focus, delete the fails and upload the decent ones. Fish photography isn't easy, I know! But remember we cannot see the fish, tank, water conditions- anything! Except what you can share with us.

Diagnosis is difficult at the best of times when non of us are aquatic vets, but sadly this is the part of the hobby where we have to do what we can with the info we have.

Can I get some clarity about the history of this issue and the tank and it's stocking, please? I'm a bit confused! Did you say you've had this same issue crop up on multiple fish before? That is usually goes away within a week or two, but this time it hasn't on this one?

What's the tank size/dimensions and complete stocking, please? So tank length, height and width, not including stand and lid. Which species of fish, and how many of each?

It's not oxygen content. The fishe's general body condition makes me think it's an older fish, and possibly one that has been in a few battles, and may have been injured by another fish, rather than a disease or illness. Either way, putting it in a separate hospital tank was the right move!

When taking the pics, if you could get a shot of the whole tank, and any other fish that you have seen with symptoms like this before could also be useful info! Sorry to chirp in just to ask a bunch more questions rather than be able to be give a simple answer! But an aquarium is a complex little ecosystem in and of itself, and there are a myriad of things that can be happening, so the more info we can gather, the better the chances someone will be able to help!

Yeah I’ll try and get better pics, sorry! It was late at night and I didn’t have great lighting. I did take a bunch and tried to filter through them as best as I could, but I’ll try again for sure now that there’s daylight hahah.

I’m sorry for the confusion! When I mentioned something I regularly deal with, I meant just normal scar tissue in the fish with longer fins. I’m fairly used to them getting a little white spot from one thing or another, but it’s not often enough or long lasting enough to have ever caused concern. When I saw white build up of the same nature under the strange bubble growth on the pink tetra, I meant that it wasn’t too concerning at first. It was only when it started to turn red like in the pics that I thought I should probably get more experienced eyes on it!

Tank wise: Currently, I have four cory cats and three Glofish tetras (two long finned and one short) in a 15 gallon tank, roughly L13x W13x H19 inches. (I’ll add a pic of the main tank now that it’s been freshly cleaned). I’ve had it since I think mid 2021? So the tetras are at least 3 years old now! They did recently loose a buddy (another long finned glo), but it’s been a few weeks. I have had issues with the long finned tetras fighting each other in the beginning, but it hasn’t been a problem in a long time now, so I’m not sure if this was a battle wound or not, especially since it’s a weird bubble of sorts?

No worries about the additional questions! Any kind of help is appreciated. I’m definitely not the best fish keeper, but I try to do as well as I can with what I got myself into! I’m not one to put their little lives in distress if I can possibly avoid it, but I’m also unfortunately a little limited.

Small updates: Looking at the pink tetra now after work, they may have uh… “popped” the bubble I suppose? As gross as that sounds. It’s not as perfectly round as it was yesterday. And now I noticed my purple tetra also has slight red dotting on a “scar” in the tail fin… so my quarantine tank has been upgraded to comfortably fit two. No one else seems to have any issue, so I kinda wonder if it was just getting into semi open wounds maybe?

 

[Seisage]

If you are dealing with open wounds, the best course of action is to do frequent water changes, about three times per week, at least. They don't have to be as large as your typical weekly change, but doing them more often will help keep the water cleaner in general and also keep bacterial counts lower which will reduce the risk of infection. Cleaning the tank isn't a bad idea either, although I'd hold off on the salt, especially if you follow the advice of frequent water changes as first aid. You would have to redose the new water with salt every time to maintain a constant concentration, which opens up more room for error. Plus, salt has the potential to be a big stressor for some fish, especially scaleless fish and those whose species comes from soft water environments. Salt is a more "powerful" medication than you'd think.

If you're confident in your ability to net out fish, you could also potentially try an application of povidone-iodine (betadine), which is a great antiseptic for wounds. Basic procedure involves netting the fish, holding it in the net over some paper towels, and using a dropper to drip a couple drops of the betadine over the wound. Let the betadine sit for a few seconds, then return the fish to the tank. You want 5% betadine, but drug stores typically only sell 10%, so dilute it 1:1 with tank water and have it prepped before you net the fish. Make sure to keep the betadine out of the mouth, eyes, and gills. Just one application would be fine, although you can repeat it multiple times if you like. It probably wouldn't help reduce whatever little tumor is happening there, but it would greatly reduce the chances of infection and may help promote healing.