Corydora covered in red splotches

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car.nelian

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Hi, I was in the middle of cleaning my tank and one of my coryā€™s swam up and i noticed that her sides covered in red marks. I thought one of my other fish had attacked her at first, but i donā€™t think itā€™s blood. I was trying to figure out what exactly it is and I read a little about red splotch disease but I wanted to get a second opinion.
 

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It very much does look like blood, it's very alarming! What other fish are in the tank? Do you have a red-tailed shark or something?
 
The water also looks quite murky, but that could just be from you having just cleaned the tank. How often do you do water changes, and how much of the water do you change at a time? Do you have a water testing kit? Size of the tank and how long you've had the fish? Any recent new additions that could have bought in disease?

Those look like injuries to me, either another fish, or panicked and swam into some sharp decor, or trapped against a filter or something perhaps.
The more details you can share about your set up, stocking, age of tank etc, the better we'll be able to help figure out the problem. :)
 
The water also looks quite murky, but that could just be from you having just cleaned the tank. How often do you do water changes, and how much of the water do you change at a time? Do you have a water testing kit? Size of the tank and how long you've had the fish? Any recent new additions that could have bought in disease?

Those look like injuries to me, either another fish, or panicked and swam into some sharp decor, or trapped against a filter or something perhaps.
The more details you can share about your set up, stocking, age of tank etc, the better we'll be able to help figure out the problem. :)
Right now I have a ten gallon tank (Iā€™m moving them to a 20 soon, but the tank is still cycling), 3 corys, 5 ember tetras, and a female betta fish. Normally I do water changes once a week, around 30-40%, but I fell a bit behind because Iā€™m graduating next week and was trying to get all the prep done. So it was closer to two weeks this time.
Iā€™ve had the corys and 3 of the embers for over a year now, and the other two embers + the betta for a few months now. I havenā€™t noticed any signs of aggression from the betta, but if she attacked my cory, Iā€™ll move her into a tank by herself.
The only major changes in the tank recently are the substrate and some of the decor. I originally had them on some gravel, but I noticed that it broke one of their whiskers, so i changed it to sand. Over the next month I added in some fluval decorations+some silk plants, because a lot of my live plants didnā€™t survive the substrate change.
 
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It very much does look like blood, it's very alarming! What other fish are in the tank? Do you have a red-tailed shark or something?
The only fish I have that I think mightā€™ve attacked her, would be my female betta. I havenā€™t noticed any signs of aggression from her, or her picking on any of my other fish, but if she attacked my cory, Iā€™ll move her to a tank by herself.
 
The only fish I have that I think mightā€™ve attacked her, would be my female betta. I havenā€™t noticed any signs of aggression from her, or her picking on any of my other fish, but if she attacked my cory, Iā€™ll move her to a tank by herself.
i reccomend you do that
this looks like some irritation or maybe red splotch disease
picture of the whole tank to see if theres any sharp deco?
water parameters?
added any chemichals to water?
 
I just finished cleaning a little bit ago, so itā€™s a little cloudy, but thatā€™s my tank. I donā€™t have a test kit, but I can get the water tested tomorrow. The only chemicals I add at the moment are Seachem Prime, Stress coat, and Seachem Flourish (Excel, and Iron) for my remaining live plants. The only decorations i have in there right now are two fluval plants, a silk plant, some slate pieces, three pieces of driftwood, and my remaining live plants.
 

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How long have you had the fish for?
Have you added anything to the tank in the last 2 weeks?
Is there black areas of sand in the picture?

The red is blood and could be from physical injuries or a bad bacterial infection.

If the fish got caught under something and scratched itself up, it should be ok, but if it's a bacterial infection, then it might die.

I would monitor it over the next few days and maybe add a little bit of salt to the tank. If it gets worse, post more pictures.

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SALT
You can add rock salt (often sold as aquarium salt) or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres 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 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.
 
I just finished cleaning a little bit ago, so itā€™s a little cloudy, but thatā€™s my tank. I donā€™t have a test kit, but I can get the water tested tomorrow. The only chemicals I add at the moment are Seachem Prime, Stress coat, and Seachem Flourish (Excel, and Iron) for my remaining live plants. The only decorations i have in there right now are two fluval plants, a silk plant, some slate pieces, three pieces of driftwood, and my remaining live plants.
Can you clarify why you are using two dechlorinators please?

Prime and Stress Coat both dechlorinate the water and could potentially conflict. Also can you confirm that the Stress Coat variant does not have Aloe Vera in the ingredients list as the Aloe is not suited for use with fish due to its inability to be diluted and the fact that it builds up in the gills as a result.

Either way you only need one dechlorinator and I would personally stop using Stress Coat and stick with Prime only.
 
How long have you had the fish for?
Have you added anything to the tank in the last 2 weeks?
Is there black areas of sand in the picture?

The red is blood and could be from physical injuries or a bad bacterial infection.

If the fish got caught under something and scratched itself up, it should be ok, but if it's a bacterial infection, then it might die.

I would monitor it over the next few days and maybe add a little bit of salt to the tank. If it gets worse, post more pictures.

--------------------
SALT
You can add rock salt (often sold as aquarium salt) or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres 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 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.
Iā€™ve had her for a little over a year. I added the large plant in the corner a little under two ago, and those dark spot are slate pieces partially buried under sand. I have them set up like little stepping stones. I have some aquarium salt downstairs, so iā€™ll get that set up tomorrow morning just in case, and iā€™ll keep an eye on her. Iā€™ll 100% update if anything happens.
 
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Can you clarify why you are using two dechlorinators please?

Prime and Stress Coat both dechlorinate the water and could potentially conflict. Also can you confirm that the Stress Coat variant does not have Aloe Vera in the ingredients list as the Aloe is not suited for use with fish due to its inability to be diluted and the fact that it builds up in the gills as a result.

Either way you only need one dechlorinator and I would personally stop using Stress Coat and stick with Prime only.
I started using it when i switched out my substrate a little bit ago. A friend recommended that I use it for a little bit after for the slime coat it puts on the fish. I plan on only using prime in the future.
 
I started using it when i switched out my substrate a little bit ago. A friend recommended that I use it for a little bit after for the slime coat it puts on the fish. I plan on only using prime in the future.
The "slime coat" provided by Stress Coat is synthetic thanks to the Aloe Vera additive which is an essential oil for humans primarily and is likely to be irritating the Cory....especially if the Cory has had any injuries in the past

Please stop using the Stress Coat immediately. Unfortunately the Aloe does not dissipate in the water, it hangs there and builds up with each water change where it is used, eventually causing gill blockage and suffocation of the fish...it can also irritate the fish.

If you do a 70% water change today and every day for the next week, the effects of the Aloe will be lessened, you might not get rid of it entirely...however since you plan to change to the other aquarium once it is fully cycled, the fish will have fresh, clean and balanced water chemistry which will help to remove any residue in the gills and body but possibly will not totally heal gill damage.

I believe that your friend's good intentions may have backfired. Whether this fish will survive is not guaranteed but do daily water changes to get the irritant levels down and hopefully things will settle down. If the fish starts acting "off" or stops eating or loses interest in its tankmates or surroundings, you may have to consider euthanising it...but that step is the last resort and down the line from now.
 
Update:
Sheā€™s looking a lot better today! Iā€™m going to do a few water changes over the next few days to help limit the effects of the stresscoat, and iā€™ll dose the water with some aquarium salt to help with the healing process. Thank yā€™all so much for all of your help!
 

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