Torn fins, messed up barbs, and excess slime coat on some of my corydoras... Whats going on with my water and fish?

The April FOTM Contest Poll is open!
FishForums.net Fish of the Month
🏆 Click to vote! 🏆

Rocky998

Kinda crazy, but somehow they let me stay
Tank of the Month 🏆
Joined
Jun 25, 2021
Messages
13,774
Reaction score
11,801
Location
NC, U.S.A
I've been noticing for a while that SOME of my corydoras (by some, I do mean a good amount. It's split though. There are some without any issues and then some with issues) have really messed up fins, broken barbs, and an excess slime coat...
I know a lot of this means bad water quality so I took tests and I'll share a photo below.
But why the bad water quality? This aquarium was cycled through well, and even if the cycle broke, it should've repaired itself from when symptoms started...
I'm very confused on why my water is like this and what's going on with my corydoras.
Also I have to add that this is Friday and my last waterchange was on either Thursday or Friday of LAST week.
Thursday-Saturdays are usually when I do my water changes
So it's been a whole week since a water change has been done.
1000002663.jpg
 
So what else is there, and do you think you could have a low grade parasitic infection going on? Some can be chronic.
 
So what else is there, and do you think you could have a low grade parasitic infection going on? Some can be chronic.
I don't think so. They all seem very healthy otherwise. It's just the fins and excess slime. Thye all eat and move normally.
Although sometimes if the fins are in really bad shape they may move a bit slower, but I see no other signs of sickness.

I have peacock gudgeons in there as well but they are not affected by any of this. No excess slime and no torn fins. If they do have torn fins it's cause the males have been sparring.
 
Look up images of Chilodonella and Costia - see if there's something to that.
 
Look up images of Chilodonella and Costia - see if there's something to that.
I don't see any signs of thst and I just spent a lot of time looking through my microscope at different settings to find any signs of it and couldn't see it... Hmm
 
Could the Tateurndina be ramming them, if they are nesting?

You do two substrate oriented fish in one tank, and Corydoras often get the brunt of territoriality. I only kept Tateurndina in single species tanks.
 
Last edited:
Could the Tateurndina be ramming them, if they are nesting?

You do two substrate oriented fish in one tank, and Corydoras often get the brunt of territoriality. I only kept Tateurndina in single species tanks.
No. I've spent countless hours in front of my aquarium.
The gudgeons haven't been nesting lately and they get along SUPER well with the corydoras.
I watch them eat together and sometimes the gudeons sleep right next to the corydoras.
They're great roommates lol. I have NEVER even seen any chasing between the two species.
 
After all the photos you put on here showing your fish and there's none here for a disease issue. Pictures of the sick and healthy fish?

Did you add anything to the tank in the last few weeks?

I'm assuming the left phial is ammonia, middle is nitrite, right phial is nitrate?

The nitrate is from the nitrite. Nitrate test kits read nitrite as nitrate and give you a false reading if there is nitrite in the water.

The nitrite is because something has happened to the filter. You might have had a power failure or the filter and tank/ substrate just needs a clean.
When was the last time you cleaned the filter?
Established biological filters should be cleaned at least once a month.

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

BASIC FIRST AID FOR FISH
Test the water for ammonia, nitrite, nitrate and pH. You did that so it's fine.

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. (You should also do this if there is a water quality issue). 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 and video of the fish so we can check them for diseases.
 
After all the photos you put on here showing your fish and there's none here for a disease issue. Pictures of the sick and healthy fish?
I was starting my water change when I made this and wasn't able to... I also didn't have something with a good camera on it at the time. Maybe I'll try today but my corydoras are SUPER skittish...
Did you add anything to the tank in the last few weeks?
Not that I can remember...
I'm assuming the left phial is ammonia, middle is nitrite, right phial is nitrate?
Yes
The nitrate is from the nitrite. Nitrate test kits read nitrite as nitrate and give you a false reading if there is nitrite in the water.
I forgot the nitrate test also reads nitrite. Thanks for the reminder on that!
The nitrite is because something has happened to the filter. You might have had a power failure or the filter and tank/ substrate just needs a clean.
When was the last time you cleaned the filter?
Established biological filters should be cleaned at least once a month.
Actually we did recently have power outages. Thursday I think ot was. BUT the issue has been going on way before that...

Last time u cleaned the filter was probably 4-5 weeks ago...

should I stop priming the filter with the straight tap water? Is that affecting it? I thought about that but wasn't sure if that was the issue...
BASIC FIRST AID FOR FISH
Test the water for ammonia, nitrite, nitrate and pH. You did that so it's fine.

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.
Will do that
Do a 75% water change and gravel clean the substrate every day for a week or until the problem is identified. (You should also do this if there is a water quality issue). 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.
Honestly I can't promise that. There's so much going on and I don't think I can do daily water changes. But I'll do larger than normal water changes weekly and clean the filters for sure.
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.
Will do!! I usually take the media bag and wash it really well in old tank water and scrub the inside of the filter with a sponge that's meant only for the tank and make sure the impeller is cleared off and stuff.
All my media sponges get dirty quick as well... It's tiring to keep up with lol.
Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.
Maybe I'll drop the tank level a bit to increase agitation next week
Post clear pictures and video of the fish so we can check them for diseases.
I'll try... But I can't promise that as my fish are super shy
 
You should fill/ prime filters with aquarium water, not tap water.

You can wash the filter case and motor under tap water, but you want to try and avoid washing the filter media under tap water.

If the fish are acting nervous/ skittish, there is a water quality issue and you need to do a huge water change to dilute anything bad in it.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.
 
You should fill/ prime filters with aquarium water, not tap water.
Yah, you're right. I'll start doing that.
You can wash the filter case and motor under tap water, but you want to try and avoid washing the filter media under tap water.
I never really wash filter media under tap water but it does come into contact with tap water when I prime it, which is stupid lol. So I'm gonna change that and start priming with tank water when the tank is filled back up.
If the fish are acting nervous/ skittish, there is a water quality issue and you need to do a huge water change to dilute anything bad in it.
Ah ok. Good to know.
Its weird cause the gudgeons are super happy and active/healthy, but the corydoras are mire sensitive im noticing.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.
After draining, I put a measuered amount of conditioner in the tank and then fill with hose water (I let the hose run for a few minutes before I use any of the water I it).

I'm strong, but am unable to lift buckets of water up and over to dump in the tank.
Plus it messes up everything in the tank when I do it.

I've heard of others using straight tap/hose water to full their tanks, especially when using the python so I assume it's ok
 
I fill my display from the tap but I use a dechlorinator before I add any water to what's left in my tank. I add about 10 gallons a week in buckets for evaporation as well. I squirt some Prime into the bucket first and than take it outside to fill with the hose. Our water pressure is really strong so when im filling the bucket it's really mixing that prime up good with the water.


Using tap to prime your filters isn't great but I don't know if that would cause what you have going on because you're priming it and it's immediately sucking water from the tank back into the filter. It's worth changing that part of your routine as fresh tap on your bacteria is all bad
 
I was starting my water change when I made this and wasn't able to... I also didn't have something with a good camera on it at the time. Maybe I'll try today but my corydoras are SUPER skittish...

When you say you've sat there for ages observing the peacocks with the cories and no issues, sleeping next to each other etc? Do that, but with your camera phone handy, and slowly and casually take snaps of them over an hour or so while you sit there and read/write/whittle, whatever you do while you sit near the tank to observe, giving the fish some time to settle and get used to you sitting near the tank pointing a phone at them. ;)

Main first question, you said you usually change water weekly, but didn't mention volume of water you usually change!
Not that I can remember...

Yes

I forgot the nitrate test also reads nitrite. Thanks for the reminder on that!

Yep, I don't like the look of that nitrite test result. It should be sky blue. That purple shade isn't good, and will have the fish stressed and make them produce excess slime etc. You've been here long enough, you know if ammonia or nitrites are above zero (and your nitrites are above zero, no doubt) then you water change it out!


Actually we did recently have power outages. Thursday I think ot was. BUT the issue has been going on way before that...

Last time u cleaned the filter was probably 4-5 weeks ago...

should I stop priming the filter with the straight tap water? Is that affecting it? I thought about that but wasn't sure if that was the issue...

Yes. At least use declorinated water if you're not wanting to take it from the tank. I highly doubt it's killing off many of your good bacteria, but it's certainly not helpful, and a bad habit worth breaking. ;)
Will do that

Honestly I can't promise that. There's so much going on and I don't think I can do daily water changes. But I'll do larger than normal water changes weekly and clean the filters for sure.

Understandable that you can't promise daily, but I'm sure you can squeeze at least bi-weekly until it's stable and fish are better. Just do it when you get chance, and aim to do it several times this week, and see if your fish and test results improve. I'm betting you will see an improvement, and it's just a case of tank perhaps being a bit under-maintained as you're busy and we all tend to slack off a bit at times, and as we get a bit complacent. When yours was always maintained regularly, skipping a water change or two no big deal, but then it can pile up, and suddenly you realise the levels have been getting off balance and fish have been low level stressed for too long.
Will do!! I usually take the media bag and wash it really well in old tank water and scrub the inside of the filter with a sponge that's meant only for the tank and make sure the impeller is cleared off and stuff.
All my media sponges get dirty quick as well... It's tiring to keep up with lol.

If they're getting that filthy that fast, are you perhaps overfeeding, under cleaning, or do you need more or better filtration? I'm guilty of not cleaning my canister filters often enough, but they still don't get that filthy that fast! Perhaps adding an internal filter that improves flow on the other side of the tank could help? Can get some pretty decent little ones that aren't crazy expensive. Or add a HOB or sponge filter. I've often run two filters plus live plants in heavily stocked tanks, and found it helpful. :)
Maybe I'll drop the tank level a bit to increase agitation next week
Adding a HOB, internal or sponge filter would do that, without the need to decrease volume. Plus, cories enjoy the flow! Not sure about the gudgeons though, not my fish. :)
I'll try... But I can't promise that as my fish are super shy
At least a pic of the tank as a whole?
Ah ok. Good to know.
Its weird cause the gudgeons are super happy and active/healthy, but the corydoras are mire sensitive im noticing.

What's the substrate? And how/how often do you clean it?
After draining, I put a measuered amount of conditioner in the tank and then fill with hose water (I let the hose run for a few minutes before I use any of the water I it).

What do you do about the temp? Mixer tap? Is there much of a temp difference between the tank temp, and the new added water temp?
I'm strong, but am unable to lift buckets of water up and over to dump in the tank.
Plus it messes up everything in the tank when I do it.

Rocky...! Putting on my motherly, naggy voice! Haha. You don't just lift a 15L bucket and tip it in... no one should do that, terrible for your back, and will make a mess of your tank, as you say! If you use the bucket method, you move the bucket near the tank (I have a low table near the tank I can put the bucket on, after putting down a fish towel) then use something like a plastic jug to add the new water a jugful or two at a time. You can use something like a disposable plastic plate on the surface to pour the water onto, so it disperses the force and doesn't just pour into the tank and make a mess of your plants/substrate/pouring it directly onto the fish... although some seem to enjoy that! My mollies do, anyhow.
 

Most reactions

trending

Members online

Back
Top