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Possibly ill bronze cory

IndiaHawker

Fish Fanatic
Joined
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England
Noticed yesterday that one of my cories has much shorter barbels than the others - from what I can make out in photos they all used to have barbels of about the same length; the others appear fine but I don't know what's happened to this one. I noticed just now that one of his or her eyes is very swollen and red-looking - I assume this is a recent development as I imagine I'd have noticed. I don't know what's caused this and considering there were no problems with the cories until both of these things happened at once - so I feel like the two could be related. But no idea if it's been caused by other fish (tankmates are a red wagtail platy, three zebra danios, and a bristlenose plec, or injury, or illness, and how to go about treating this if possible/advisable? I don't have a quarantine tank :/ Would really appreciate some help, please and thank you!
 
When corydoras lose barbels it's because either the gravel is too sharp or dirty gravel. As for the red thing on the eye, that's caused by a bacterial infection.
 
Is there just a red spot? If so that is red blotch disease.
 
Also red blotch disease has symptoms like selling in one eye or both.
 
Okay thank you! It's not due to gravel as they have sand. I do have some rocks but the cories hide behind/between them and are rarely/never actually rooting around on the rocks. The others have perfect-looking barbels. It's not so much a red 'spot' as one red swollen eye - I will do my best to get a good close-up photo asap to post on here!
 
There has been a build-up of dirt (soft muck) in places on the sand recently though - Sarah you mention dirty gravel, could dirty sand be the problem and if so how does it cause this? Please and thanks!
 
Do a 75% water change and gravel clean the substrate each day until this is resolved.

Clean your filter if it hasn't been done in the last 2 weeks.

Gunk (fish waste and other rotting things) sit in and on the sand and cause bacteria and other microscopic organisms to grow. The fish get the bacteria on them and it can make them sick.

Do a big water change and gravel clean, post a photo of the sick fish, then we can talk about medications. But try water change and gravel clean first.
 
Yup, when dirt gathers in sand that can cause a bacterial infection. Clean it up asap. What are you feeding them? The barbels will grow up quickly with clean water. And @Colin_T What do you mean by clean? Lile clean the filter pads completely?
 
If you have a power filter it should be cleaned at least once a month or preferably more often. Squeeze out the filter materials in a bucket of tank water and when it's clean, rinse them in a second bucket of tank water. Then put the media in the aquarium.

Wash the filter case and motor under tap water, then set the filter up and get it running again.
 
Hi, thanks so much all. Will do water change asap (but have a few more questions before I do anything wrong) and make sure to use the gravel vac on the substrate - I wasn't worried about the muck it as I was under the impression that although it looks unsightly (wasn't a huge amount of muck though) it was good for the ecosystem, didn't realise that it could cause this. I normally always clean out the sponge but haven't done the pump itself for a few weeks so will do this too.

I forgot to mention I've been having problems with nitrates in my tap water, I've recently purchased a pozzani tap water filter and done everything right as far as I know - ran the hose through for a few minutes first to wash out softening agents, ran the filter through itself for five minutes before filtering water for my tank as instructed, tested filtered water before putting it in my tank. Could the nitrates have caused my fish's illness?

And my main question - the pozzani filter lowers my pH from ~8 to 7.2 - but is necessary due to the high nitrate content of my tap water, plus I believe the lower pH will be better for my fish. My last water change (sunday) was a smaller one as it was my first time using the pozzani filter and I didn't want to drastically alter the pH of the tank all at once. So for my asap water change, what should I do? Should I do a large water change using the pozzani-filtered water and risk changing the chemistry of the tank water significantly and stressing the fish? Or should I go back to my old method whilst this fish is unwell which would mean adding in water high in nitrate content, but not different to what they're used to and not a shock? Bit of a catch 22 and I'm totally new to illnesses like this therefore I'm feeling very lost!

I did however manage to get some relatively clear photos today:

DSCF1592-min[1].JPG
DSCF1594-min[1].JPG
DSCF1600-min[1].JPG


As you can see the eye is very red and swollen-looking, plus some patches of scales appear to look pale and discoloured. I'm also wondering if the pale thing pictured a bit to the bottom left of the eye could be something, or possibly just a clump of sand (was hard to see up close without the camera's zoom). I imagine it more likely to be something relating to this.

Also I feed my fish flake food and two algae pellets a day (bristlenose pleco, 4x bronze cories, 3x zebra danios, and a red wagtail platy) - been looking into frozen foods for them but will hold off if advised whilst the fish is unwell (I assume not good because could add more bacteria into the tank)?

I hope the pictures can bring some clarity to this - could my other fish catch this? I'm worried and just want to make my poor cory cat better. Would really appreciate some more help please and answers to my questions - in particular the one regarding which water to use for the water change/s whilst my fish is unwell. Please and thank you!
 
Last edited:
Use the filtered water. Are you measuring the pH out of the tap / filter or in the tank? The Pozzani filter should have no impact on pH but filtering the water could have a similar effect to letting it stand for 24 hours as the water will get aerated by the filtering process.

Your sand doesn't look too dirty and your filter maintenance sounds ok. I wouldn't add any treatments at this stage but keep an eye for the next week or so.

Do you know if this is your original cory or one of the ones you added?
 
Nitrates did not cause this.

How long have you had the catfish for?
Have you added any new fish during the last 2 weeks?

----------------------
The red eye looks like physical damage, eg: the fish got hit in the eye by something or damaged it somehow. The red in the eye is blood that has collected there due to the damage. If it is physical damage, then it should heal up by itself. The fish might be blind in that eye due to the damage, but time will tell.

----------------------
The white patching on the body is either excess mucous produced by the fish in response to something in the water, (poor water quality or protozoan parasites) or a bad fungal infection.

----------------------
If nothing new has been added to the tank in the last 2 weeks and none of the other fish have cream, white or grey patches on their body, then it is probably fungus and should be treated asap with a broad spectrum medication that treats bacteria & fungus. You want to treat for bacteria as well as fungus to make sure the eye doesn't develop an infection due to the damage.

If you have added new fish or plants during the last 2 weeks, use a medication that treats bacteria, fungus & protozoan infections.

Because it is a catfish you should check the directions for using any medication on scaleless fishes (catfish, loaches, eels). If there are no directions for scaleless fish, then use the medication at half strength.

----------------------
To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.

When you measure the height, measure from the top of the substrate to the top of the water level.

There is a calculator/ converter in the "How To Tips" at the top of this page that will let you convert litres to gallons if you need it.

Remove carbon from the filter before treating or it will absorb the medication and stop it working.

Wipe the inside of the glass down, do a 30-40% water change and complete gravel clean if possible. The water change should not drop the pH too much and will help remove some of the unwanted microscopic organisms in the water. And clean the filter before treating if you haven't done it in the last 2 weeks.

Increase surface turbulence/ aeration when using medications because they reduce the dissolved oxygen in the water.

Treat him now if you can, or as soon as possible.
 
Hi, thanks so much all. Will do water change asap (but have a few more questions before I do anything wrong) and make sure to use the gravel vac on the substrate - I wasn't worried about the muck it as I was under the impression that although it looks unsightly (wasn't a huge amount of muck though) it was good for the ecosystem, didn't realise that it could cause this. I normally always clean out the sponge but haven't done the pump itself for a few weeks so will do this too.

I forgot to mention I've been having problems with nitrates in my tap water, I've recently purchased a pozzani tap water filter and done everything right as far as I know - ran the hose through for a few minutes first to wash out softening agents, ran the filter through itself for five minutes before filtering water for my tank as instructed, tested filtered water before putting it in my tank. Could the nitrates have caused my fish's illness?

And my main question - the pozzani filter lowers my pH from ~8 to 7.2 - but is necessary due to the high nitrate content of my tap water, plus I believe the lower pH will be better for my fish. My last water change (sunday) was a smaller one as it was my first time using the pozzani filter and I didn't want to drastically alter the pH of the tank all at once. So for my asap water change, what should I do? Should I do a large water change using the pozzani-filtered water and risk changing the chemistry of the tank water significantly and stressing the fish? Or should I go back to my old method whilst this fish is unwell which would mean adding in water high in nitrate content, but not different to what they're used to and not a shock? Bit of a catch 22 and I'm totally new to illnesses like this therefore I'm feeling very lost!

I did however manage to get some relatively clear photos today:

View attachment 88938 View attachment 88939 View attachment 88940

As you can see the eye is very red and swollen-looking, plus some patches of scales appear to look pale and discoloured. I'm also wondering if the pale thing pictured a bit to the bottom left of the eye could be something, or possibly just a clump of sand (was hard to see up close without the camera's zoom). I imagine it more likely to be something relating to this.

Also I feed my fish flake food and two algae pellets a day (bristlenose pleco, 4x bronze cories, 3x zebra danios, and a red wagtail platy) - been looking into frozen foods for them but will hold off if advised whilst the fish is unwell (I assume not good because could add more bacteria into the tank)?

I hope the pictures can bring some clarity to this - could my other fish catch this? I'm worried and just want to make my poor cory cat better. Would really appreciate some more help please and answers to my questions - in particular the one regarding which water to use for the water change/s whilst my fish is unwell. Please and thank you!
Ok I see the problrm. Algae wafers have no value to corydoras. They are meat eaters. His system started to get weak because he wasn't being fed the proper diet which caused him to be more prone to diseases. Go get your corydoras some shrimp pellets, blood worms, and brine shrimp.
 
Again, thanks all for the help!

Ok I see the problrm. Algae wafers have no value to corydoras. They are meat eaters. His system started to get weak because he wasn't being fed the proper diet which caused him to be more prone to diseases. Go get your corydoras some shrimp pellets, blood worms, and brine shrimp.

Oh wow I feel awful! I had no idea and will buy some online tonight with fastest delivery possible. Does the flake food have any meat in or not? I assume this is mostly irrelevant though as the cories are bottom-feeders. Thanks so much for letting me know this, I've been looking into all fish the best I can but just totally missed this :/

Nitrates did not cause this.

How long have you had the catfish for?
Have you added any new fish during the last 2 weeks?

----------------------
The red eye looks like physical damage, eg: the fish got hit in the eye by something or damaged it somehow. The red in the eye is blood that has collected there due to the damage. If it is physical damage, then it should heal up by itself. The fish might be blind in that eye due to the damage, but time will tell.

----------------------
The white patching on the body is either excess mucous produced by the fish in response to something in the water, (poor water quality or protozoan parasites) or a bad fungal infection.

----------------------
If nothing new has been added to the tank in the last 2 weeks and none of the other fish have cream, white or grey patches on their body, then it is probably fungus and should be treated asap with a broad spectrum medication that treats bacteria & fungus. You want to treat for bacteria as well as fungus to make sure the eye doesn't develop an infection due to the damage.

If you have added new fish or plants during the last 2 weeks, use a medication that treats bacteria, fungus & protozoan infections.

Because it is a catfish you should check the directions for using any medication on scaleless fishes (catfish, loaches, eels). If there are no directions for scaleless fish, then use the medication at half strength.

----------------------
To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.

When you measure the height, measure from the top of the substrate to the top of the water level.

There is a calculator/ converter in the "How To Tips" at the top of this page that will let you convert litres to gallons if you need it.

Remove carbon from the filter before treating or it will absorb the medication and stop it working.

Wipe the inside of the glass down, do a 30-40% water change and complete gravel clean if possible. The water change should not drop the pH too much and will help remove some of the unwanted microscopic organisms in the water. And clean the filter before treating if you haven't done it in the last 2 weeks.

Increase surface turbulence/ aeration when using medications because they reduce the dissolved oxygen in the water.

Treat him now if you can, or as soon as possible.

One catfish I've had since July, the other three I've had for at least a month - no new fish since I added the three cories. Wow I'm surprised that it could be physical as no fish appear aggressive towards the cories but could be the case I guess - the only thing that crosses my mind is that when I do water changes, I pour the water back in using a small bowl but have been intentionally creating some (not major) disturbance with the aim of preventing stagnant spots and moving out any muck that's stuck between plants/rocks. I'm wondering if in doing this I could possibly have knocked the cory into a rock and hurt him (the rocks aren't particularly sharp and have been there for months with the cories swimming and hiding between them and no issue, hence why I'm considering myself to have caused this during a water change). If so, and disturbing the water whilst pouring the water back in is a bog no-go, how do others refill their tanks please? Just really really carefully, or what? And do you think the barbel loss has been caused by physical damage or illness?

Interesting, so you think the patches on the body could be caused by something different to the physical injury? Do you think they could be related or just co-incidentally happened around the same time? Nothing new has been added to the tank for a fair bit longer than two weeks (the last thing was three of the cories I believe) and I can't spot any patches on any other fish so I will assume it to be fungus and try to find the appropriate medication online. If I'm wrong and it's not fungus, could I harm the fish? And thank you for the tip about medicating catfish - I'd totally forgotten that catfish are scaleless and have 'bony plates' instead if I remember correctly?

Thank you for the tip on measuring water volume - my tank is bow fronted (fluval flex 57) and the bow goes the opposite way to a usual bow front if that makes sense? But I'm assuming I'll need to know the volume of water to best medicate, so a bit worried. Also I have a fair few rocks (you can see in my profile picture) so could this make the calculations really off? I assume it's better if unsure to use too little medication rather than too much? Also I will look online and try to find the best medication but if you could recommend me any specific names or brands I'd really appreciate it as a bit clueless! Will make sure to remove carbon, thanks!

I will do the water change as you described, should I avoid doing a larger one on case I affect pH too much too quickly? And also do you still recommend the daily water change or not having seen the pictures and knowing more about what's causing this? Will make sure to clean the filter, I do it pretty regularly but it's probably been a few weeks come to think of it (I do the sponge and filter media weekly but not always the pump itself).

Thanks for the tip about surface disturbance too - does this still apply although I use an air pump? Can work with that pretty easily anyway!

Thanks so much for all the help and knowledge!

Use the filtered water. Are you measuring the pH out of the tap / filter or in the tank? The Pozzani filter should have no impact on pH but filtering the water could have a similar effect to letting it stand for 24 hours as the water will get aerated by the filtering process.

Your sand doesn't look too dirty and your filter maintenance sounds ok. I wouldn't add any treatments at this stage but keep an eye for the next week or so.

Do you know if this is your original cory or one of the ones you added?

Okay will do! The much lower pH was measured from the bucket of filtered water before adding it to the tank - I can't remember if there was a visible difference in pH in the tank itself after the water change but I did note it down so I'll check! I did do a smaller water change than usual though but interesting to know, thanks!

The sand isn't too bad and looks better now than it first did after the water change - now unsure what to do medication-wise as reading conflicting opinions! Like I'd rather be on the safe side and use medication if it could help, I've just been paid (thank god) so I have some money to spend at the moment if I need to - but then I don't want to medicate if unnecessary and could cause harm instead of helping?

Hate to say it but I really can't tell which cory this is - I've been trying so hard since getting the other three to work out which is Dory the Cory but I just can't tell - I was originally stuck between one of two and at the moment I have no idea!

Thanks so much for all the help!
 
What kind of fish flakes do you have? Doubt it as fish flakes have very little protein.
 

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