Very Sick Cory - Red Blotch Disease?

[DoubleDutch]

The substrate is for planted tanks. It is new but has been cycling for like a year.

Were they on this substrate before ?

 

[FashionFish]

Were they on this substrate before ?

hi double dutch - the bronze cories were on a sand substrate. our sterbais and everyone else have lived on a planted soil for the 3 years since we have had them.

 

[FashionFish]

Dang, I'm sorry

Weird that the cory passed despite using the prime, but you never know what damage may have been done internally if there had been an ammonia spike. But if it's RO you're using, then the ammonia isn't coming from the source water (sometimes tap water can give a low ammonia reading due to ammonium in the water).
I'm suspecting it was an ammonia spike based on there still being ammonia readings and the fish symptoms, but it's still possible it's something else. So can we try to get a larger picture please?

Tank size, so it's a 50 US gallon?
Total stocking?
When were fish added? Were they only fish you already owned, or any new ones bought in?
What filter are you using? Do you change filter media out, like cartridges? How do clean the filter media?

hi adorabelle,

i can upload a picture of the aquarium later today.

it is a 65 US gallon tank, but with the soil & rocks there is more like 50 gallons of water.
for stock we have:
3 Bronze cories (had 4 - lost one yesterday)
6 Sterbai (1 adult & 5 juveniles)
1 Golden Albino Bristlenose
1 Amano Shrimp
1 Nerite Snail
2 Assassin Snails

All of them have been with us for 3 - 4 years, except the juvenile Sterbai which were recently added.

We have a JBJ aquarium. It has filter socks which you can rinse or replace. We also added ceramic rings and fresh carbon.

 

[FashionFish]

Just wanted to say I have 30 US gallons of new water priming. We are re-rinsing the socks and are then going to soak the socks in prime and water before putting back into the tank. Will update with the test results later. Thank you

 

[AdoraBelle Dearheart]

Just wanted to say I have 30 US gallons of new water priming. We are re-rinsing the socks and are then going to soak the socks in prime and water before putting back into the tank. Will update with the test results later. Thank you

What's inside the filter socks? Sorry, not familiar with those or how they're used!
What kind of water are you soaking them in? Because cleaning any part of the filter media in tap water would kill a significant portion of the beneficial bacteria. Must only rinse/clean soak the media in tank water, or declorinated water (such as treated tap, or your RO).

@Colin_T would really appreciate your thoughts on this, turning into a bit of a mystery, apart from that low level reading of ammonia, which still makes me a bit sus since RO wouldn't have ammonia

 

[FashionFish]

What's inside the filter socks? Sorry, not familiar with those or how they're used!
What kind of water are you soaking them in? Because cleaning any part of the filter media in tap water would kill a significant portion of the beneficial bacteria. Must only rinse/clean soak the media in tank water, or declorinated water (such as treated tap, or your RO).

@Colin_T would really appreciate your thoughts on this, turning into a bit of a mystery, apart from that low level reading of ammonia, which still makes me a bit sus since RO wouldn't have ammonia

hi there,

the filter socks act as filtration, catching debris. the media (carbon, etc) sits underneath. i am attaching a photo.
we are rinsing the socks with filtered water.
also attaching photo of the tank if that help.

thank you!

 

[Colin_T]

@Colin_T would really appreciate your thoughts on this, turning into a bit of a mystery, apart from that low level reading of ammonia, which still makes me a bit sus since RO wouldn't have ammonia

You expect me to read all this

Can someone sum this thread up in a few sentences and bring me up to date on what is going on?

 

[Essjay]

Summary for Colin

OP suspects red blotch disease. There are 2 photos in post #1, one of bronze cories and one of sterbai cories. Other members say it doesn't look like red blotch disease.
65 gallon tank.
Tank cycled before adding fish, and new plants added.
Ammonia almost 0, nitrite 0, nitrate 0. Temp 25 deg C.
10 to 20% water changes daily since the problem first noticed.
Water source does not seem to be tap water as this phrase was used in post #8, but Prime added to all water.

We did the 20% water change (10 US Gallons) And ordered more water to be delivered.

Substrate is live soil. Bronze cories were kept on sand but sterbais and other fish kept on this soil for 3 years.
Media seems to be filter socks (see post #21), ceramic rings and carbon.

Thread started 2 days ago, and yesterday it was reported that "all guys flashing and lost a cory"
Tank inhabitants

3 Bronze cories (had 4 - lost one yesterday)
6 Sterbai (1 adult & 5 juveniles)
1 Golden Albino Bristlenose
1 Amano Shrimp
1 Nerite Snail
2 Assassin Snails

All of them have been with us for 3 - 4 years, except the juvenile Sterbai which were recently added.

 

[Byron]

I would put the problem down primarily to the substrate. Cories should never be kept over anything but inert sand. These plant substrates and certainly soil can harbour various bacteria which do affect cories. It can take some time to see effects, as here. But I would guarantee that if these cories were over smooth sand they would not have this issue.

 

[DoubleDutch]

I would put the problem down primarily to the substrate. Cories should never be kept over anything but inert sand. These plant substrates and certainly soil can harbour various bacteria which do affect cories. It can take some time to see effects, as here. But I would guarantee that if these cories were over smooth sand they would not have this issue.

Agree. I don't have scientific evidence but I have seen and often seeing issues with this substrate vs Corys. What puzzles me is that the Sterbai have beem on it for three years, without this issue.

It defintely isn't Red Blotch

 

[FashionFish]

Agree. I don't have scientific evidence but I have seen and often seeing issues with this substrate vs Corys. What puzzles me is that the Sterbai have beem on it for three years, without this issue.

It defintely isn't Red Blotch

Thank you DoubleDutch & @Byron

I wanted to ask about the Red Blotch because I would not want to add meds if I wasn't sure. But I will move away from that.

I am bummed to hear you think it nay be the substrate. The guys that were struggling the most are the cories that were on sand in their tank.

 

[Byron]

Thank you DoubleDutch & @Byron

I wanted to ask about the Red Blotch because I would not want to add meds if I wasn't sure. But I will move away from that.

I am bummed to hear you think it nay be the substrate. The guys that were struggling the most are the cories that were on sand in their tank.

I had the impression the cories were all together now, and the substrate was the plant one as shown in the photos.

On a general note, several things can impact a fish, and when talking cories a prime factor is substrate. Cories must have sand because that is how they feed--they take a mouthful of sand, filter out any food, and expel the sand out via the gills. This method of eating is part of the genetic makeup of the species, so they "expect" it. Second aspect of this is that bacterial issues develop in gravel which do not occur with sand because of the grain size. Third aspect is bacterial issues from these "plant" substrates. These aspects will at the least cause stress and issues, which weakens the fish so other problems are more likely to occur. Eliminating as many aspects that are troublesome is the key to healthier fish.

 

[Colin_T]

I can't see red blotches on the catfish but if they have red areas on the skin, it is usually bacterial and normally caused by a dirty environment.

Byron is probably correct on this if the plant substrate hasn't been cleaned regularly, it could harbour all sorts of microscopic organisms that are irritating the new Corydoras.

If the plant substrate is releasing any ammonia, that will irritate bottom dwelling fishes well before it impacts fish living higher in the water column.

Try doin a 75% water change and gravel clean the substrate every day for a week. See if it helps. It might not but I would say the plant substrate is at least partly responsible for pink or red skin that might be on the fish.

Clean the filter too if it hasn't been done in the last 2 weeks. Wash filter media/ materials in a bucket of tank water and re-use the media. Pour the bucket of dirty water on the lawn.

 

[FashionFish]

I had the impression the cories were all together now, and the substrate was the plant one as shown in the photos.

On a general note, several things can impact a fish, and when talking cories a prime factor is substrate. Cories must have sand because that is how they feed--they take a mouthful of sand, filter out any food, and expel the sand out via the gills. This method of eating is part of the genetic makeup of the species, so they "expect" it. Second aspect of this is that bacterial issues develop in gravel which do not occur with sand because of the grain size. Third aspect is bacterial issues from these "plant" substrates. These aspects will at the least cause stress and issues, which weakens the fish so other problems are more likely to occur. Eliminating as many aspects that are troublesome is the key to healthier fish.

Hi Byron & @Colin_T

Byron, sorry for the confusion. All cories are in the same tank now. Bronze were previously on sand, the Sterba have been on the fluval planted soil for the years we have had them. Everyone is in the tank in the photo now.

I appreciate the feedback from you guys. I did not know that the fluval planted soil was unhealthy for cories. We did not have any health issues like this with the previous set up. Because this is a larger tank there is much more soil, so maybe it is still releasing ammonia. I am not exaggerating when I tell you that we cycled this tank for almost a year.

Thank you Colin for the advice. We are a doing a water change. We did rinse and out the media a few days ago. I do have a question about the water changes. 75% feels like a lot of water to change - could that put the fish into shock? I know we are trying to get the bad stuff out, but I did want to double check on if the amount much water being changed daily?

Thank you!!

 

[Colin_T]

If you do regular (weekly) water changes, the aquarium water and tap water should have similar water chemistry values (GH, KH, pH). So doing a large water change (75-80%) won't harm the fish as long as the new water has a similar temperature to the aquarium water, and the new water is free of chlorine/ chloramine before it's added to the tank.

The substrate might not be releasing anything now but there might be gunk trapped in it that could be contributing to skin irritation. Gravel cleaning the substrate at least once a month would help remove a lot of the harmful disease organisms that live in rotting fish waste.