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Poorly Cory

Abi Jones

Member
Joined
4 Jul 2019
Messages
51
Location
Southampton
My poor Cory is in a bad way, can anyone suggest a course of action? This started yesterday and seems to be spreading rapidly, water tests fine. I had the same thing happen to another Cory a few weeks back and it died, I can’t put it in quarantine tank as have molly fry in there at the moment. Can I add some aquarium salt maybe? It’s a 125 litre tank and have had the Corys for a couple of years.
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Either that or a wound. Increased water changes will help if it's ammonia, and if it's a wound they will help to stop it getting infected. A lot of us don't have much faith in test kits, I wouldn't be too sure that ammonia is not the problem even though your water tested OK.
I suggest a big water change with dechlorinated water pre-warmed to tank temperature, then get back to us with more information about your fish and their tank, as much as possible really, including;
What other fish are in the tank?
Are they healthy?
Is there anything sharp he could have scratched himself against?
Or somewhere he could have got stuck and hurt himself wrigglig free?
 
It’s worth getting expert advice but for what is worth: I’ve had worse than that heal after treatment. I netted the fish and gently patted the area dry with kitchen towel. I then applied a good coating of Aloe Vera gel as a temporary slime coat. Maybe I was lucky but the fish was fine after a few days.
 
Ammonia poisoning usually shows on the gills. This could be a blood infection/septicemia or haemorrhage, not much you can actually do in these cases. Maybe move to quarantine and use API stress coat? hopefully it heals over time.
 
Ammonia “burn” at that level will cause significant to complete fin disintegration

It looks as if there was a physical impact (which seems unlikely ... unless fish somehow leapt out of water, hitting hardscape, floor etc) but internal bacterial infection seems far more likely (the red appears from localized hemorrhage and base of the caudal fin is not uncommon), it may also be viral in origin (viral hemorrhagic septicaemia)

Unfortunately none of the above are able to be treated in a home aquarium but supportive care can assist fish in healing

Daily water change (50% if you already change that amount weekly, otherwise begin with 25% daily for a 5 days, then 50% daily - the large water changes will remove waterborne pathogens, eg, bacteria, virus particles etc

Vacuum substrate to remove debris etc (again this can be a significant source of bacteria etc)

Wipe down glass (biofilm including more bacteria)

Reduce temperature - bacterial infections may respond to lowered temperatures
eg, Corydoras aeneus Temperature: 21 – 27 °C
So depending upon other fish in tank, lower temperature by 1-2* daily

Do not add salt for Corydoras, note that salt acts as an irritant to fish, stimulating increased production of skin secretions - which may or may not be beneficial
Salt may also assist in alleviating symptoms of nitrite poisoning ... but water changes would also be effective


As you’ve had the Cory’s for a couple years, the condition would have developed in your tank ... I suspect the gravel contains high levels of bacteria
- is there obvious debris in syphon tube when you vacuum the gravel?
 
Thanks so much for all the reply’s. I bought the tank second hand a couple of years ago, the corys came with the tank. I’ve always hated the gravel tbh but haven’t wanted to upset the tank by changing it, the tank came with the 1 pearl gourami, 3 corys, a rasbora, about 14 black striped tetras, a rummy nose tetra, a couple of chain loach and a white tip tetra, and lots of plants. . The black stripe tetras never looked healthy and have died off gradually, I now have 5 left. The rasbora and white tip also died.
Current stock is:
2 albino Cory
5 gourami
2 molly
1 rummy nose tetra
4 chain loach
2 wood shrimp
1 Armano shrimp
1 SAE ( we did have 2 but lost one a few weeks back. It injured an eye then gradually became listless and stopped eating and died)
Lots of blue shrimp which are reproducing constantly
Filtration is a fluval 303 canister filter and a large sponge filter, tank also has co2 injection, rocks and wood and a lot of plants, mainly java fern. Temp is usually around 26 but with the hot weather has been creeping up, it currently 27.5. I do weekly 50% water changes and yes a lot of funk comes out with the gravel vac. With all the plants etc it’s impossible to vac all over tho.
One thing to note which I’m worried may be the cause of this is that I took some of the gravel out to use in the spare tank when I moved the molly fry, and I wonder if taking that gravel kicked up some detritus into the water? But I use api test kit and ammonia and nitrite show 0, nitrate is always fairly high at 40
 
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Oh I forgot there are also 3 ottos. Here is a pic of the tank. I know the gouramis need more space- I originally bought them from pets at home and didn’t realise their adult size. I have a 280 litre tank in the garage which I plan to replace this with when I have the money to buy a bigger filter substrate and lighting.
 
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