My Corydoras are slowly dying

[Colin_T]

The Corydoras panda is covered in excess mucous (creamy white film over the body). This is caused by something in the water irritating the fish. It can be from ammonia, nitrite, nitrate, plant fertiliser, medication or anything else. It can also be caused by external protozoan parasites but that normally caused white patches, and your fish is completely covered, which suggests something in the water.

Salt will treat most external protozoan infections.
Big daily water changes (for 1 week) will usually fix water quality problems.

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The Corydoras sterbai is really skinny and has blood patches on its underside. This can be something in the water (chemicals or external parasites) or physical injuries.

What are you feeding the fish and how often are you feeding them?
Try feeding it frozen (but defrosted) foods 3-5 times per day for a couple of weeks. You can use brineshrimp, bloodworms, daphnia, prawn/ shrimp.

 

[N_F_S]

The Corydoras panda is covered in excess mucous (creamy white film over the body). This is caused by something in the water irritating the fish. It can be from ammonia, nitrite, nitrate, plant fertiliser, medication or anything else. It can also be caused by external protozoan parasites but that normally caused white patches, and your fish is completely covered, which suggests something in the water.

Salt will treat most external protozoan infections.
Big daily water changes (for 1 week) will usually fix water quality problems.

-------------------
The Corydoras sterbai is really skinny and has blood patches on its underside. This can be something in the water (chemicals or external parasites) or physical injuries.

What are you feeding the fish and how often are you feeding them?
Try feeding it frozen (but defrosted) foods 3-5 times per day for a couple of weeks. You can use brineshrimp, bloodworms, daphnia, prawn/ shrimp.

This one, are in the low tech and no fertilisers.
Only have Ada Sand, Ada Soil, Water, Prime. Do you think, the problem is my water? In Portugal, the water are very controlled, and with strict parameters, and I add Prime in every WC.

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I don't think that can be injured, I don't have sharp objects or big/agressive fish.
Chemicals, again, this one has only pressurised CO2, Tropica Fertiliser, Prime, Tap Water.
How to act against external parasites?

Food:

Everyday divided in 3 times: (For 30 Corydoras)

• 5 hikari Sinking Wafers - https://www.hikari.info/tropical/t_03.html
• 1 hikari Algae Wafers - https://www.hikari.info/tropical/t_04.html
• And when feed the other fish with Hikari Micro Pellets - https://www.hikari.info/tropical/t_02.html, I overfeed to ensure the bottom fish have some too.

Every other day

• Gamma Frozen Brineshrimp + Omega 3 - Gamma Brineshrimp with Omega 3

With the Pellets and Wafers, I think everyone can eat. The Amano Shrimps, stole the sinking wafers, so I divide them in multiple parts and try to sink in different places. I know, the Corydoras that lives most of the time in the sand, can eat the wafers, but the ones that are hiding in the heavily planted area, I can't confirm if they eat. Even the food left by the other fish, usually sink in the sand area. But when I give wafers, most of the hidden ones, apear to eat..

My main problem is with the frozen food. Brineshrimp is to light, and takes a lot to sink, and I think the Corydoras can't take any part of it. Any suggestion?

Starvation can lead to red gills and body?
If I recognise him well, it's my first sterbei, and has almost 2 month with me. If I'm right, he is always on the sand and I see him eating. Probably he stop to eat after get sick.

Do you think I should feed even more?
To feed frozen food 5 times day, do you have suggestion to ensure they get their share on the bottom?

 

[N_F_S]

One extra note regarding water.

I never get a 100% Crystal water. Always have very small particles when looked very near the glass. But the problem usually intensify during the photoperiod. Seems little better when ligths on and worst when ligths off.

 

[Colin_T]

The problem could be caused by one of the things you add to the tank (plant fertiliser, ada soil or something else). Anything that irritates the fish can cause excess mucous.

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If you didn't add any new fish within a couple of weeks of this starting, it is unlikely to be an external protozoan infection. However, you can treat external protozoan infections with salt.
Use 2 heaped tablespoons of rock salt for every 20 litres of water. Keep the salt in there for at least 2 weeks but no longer than 4 weeks.

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Frozen foods that are defrosted are generally better than dry foods like pellets and wafers. Your cloudy water is probably from the dry food (wafers).

Starvation does not directly cause red gills or patches on the body. However, starvation weakens the fish and makes it more likely to catch something or get sick. Then the sores appear and the fish has more trouble fighting the disease because it is sick and malnourished.

Feed the other fish with some flake and let them eat a bit. Wait a few minutes and then feed frozen food that has been defrosted. Put a small bit of food in and let them eat it all, then add a bit more food. Continue adding food a little bit at a time until all the fish have eaten and are full. Then stop feeding and remove uneaten food.

 

[N_F_S]

UPDATE:

After the Myxazin and salt treatment, and without results, in order to fight possible external parasites, I started with waterlife octozin. The treatment is 3 doses in the first 3 days, but the meds are slowing absorption and takes 7 days to finish the treatment.

In the same day, I started with bloodworms 4x a day.

I'm current in day 4, of booth Octozin and bloodworm feeding, and since day 2 I can see improvements. Since day 2, they are very active after the first meal, swimming in the filter and powerhead outputs, even eating in the top of the tallest plants (without fear).

Today, at day 4, I saw two Jullis in T position along the front and back glass. Inspecting all the gills, sterbei seems 100% in good shape, and Jullis has some red gills but in much less extend than before, almost imperceptible.

I hope don't go back after the treatment.