Can corydoras die from gravel?

[Colin_T]

Corydoras have been dying off one by one. Symptoms are lethargy, losing weight, curved spine, and dying a day or two after showing symptoms. I've noticed that there's blood, but only on the dead fish, the living fish never bleed.

Need a better picture but the Corydoras in the picture is rather unwell. It has damage to the tail and fins, excess mucous, a damaged nose and no barbels, the skin colour looks wrong and the eyes appear to be sticking out more than they should be. This would suggest a disease and probably a bacterial infection.

How quickly do they lose weight?
What does their poop look like?
Are they eating well?
Where is the blood located on the dead ones?
Have you got any pictures of the dead fish?
Did you add anything to the tank in the 2 weeks before this started?

I'm assuming the tank gets regular water changes and gravel cleaning, and the filter is working correctly?

 

[DoubleDutch]

Because my fish die a day or two after showing symptoms. I did clean the filter when I noticed they weren't okay. There aren't external symptoms and I thought it might be internal parasites or gill flukes, but others told me these conditions wouldn't kill that fast.

As said the Cory in the pic seems to have no barbells. If so : there are external symptoms.

Also earlier mentioned : Stick to one thread.

 

[TwoTankAmin]

Corys use their barbels to taste out where there is food. The key to substrate is it cannot be sharp because edges can damage the barbels and they can get infected and disintigrate. As noted in the wild cories will feed on sand, on grave and even on plain rock bottoms. It doesn't matter because in the wild they are all smooth.

Smaller sized gravel is a bit better for one specific reason. The food particles can fall deeper down in larger gravel which has more spaces between the pieces and the corys will then be scraping their barbels trying to reach the food. The deeper the gravel, the harder it is to get down to food deeper down.

I had the privilege of meeting Ian Fuller at one of the bi-annual CatCon (Catfish Convention) weekends outside of Washington DC. I took the opportunity to thank him for all the great information he has shared with hobbyists over the years and to shake his hand. What you can read blow is taken from his site.

Starting with Corydoras​

New to Corydoras Catfish? Read this!​

Before considering keeping any species of Corydoras, whether they are common or rare there are a few things to that need to be looked at, and a few questions to be asked.

Firstly and the most important item of consideration is the environment in which they are to be housed. Most Corydoras species will live quite happily in a relatively small aquarium, a single pair of fish in a 25 cm x 20 cm x 20 cm (12' x 8" x 8") tank would do fine, but if you want to give them some company! Say another three or four mates of the same species and a few tetras or Barbs, then larger surroundings would be a must, a tank of 60 cm x 30 cm x 60 cm (24" x 12" x 12") would be a good size to start with.

The equipment and decoration to a certain degree is all a matter of choice, but there are some areas that should be given careful consideration, the main one of these is the substrate that is to be used. My recommendation is the use of fine smooth gravel or a course grained smooth sand, to a maximum depth of 15 millimeters this allows the catfishes to reach through to the base glass of the tank and find all the particles of food that have penetrated deep into the substrate.

I emphasize the smooth because this is extremely important when it comes to keeping Corydoras in the best of health and condition. Any sharp edged sand or gravel can very quickly damage the delicate barbels of these busy little fishes, this damage in turn can lead to bacterial infection and fugal attack which may in turn be fatal.

edited for spelling and typos

 

[VioletThePurple]

Somewhere way back in all these threads I suggested Mycobacter. That view hasn't changed.

What is that? Bacteria?

 

[TwoTankAmin]

This is more than you want to know about Mycobacteria
https://www.sciencedirect.com/topics/medicine-and-dentistry/mycobacteriu

There are about 140 or more different mycobacteria. The one we have all heard of causes tuberculosis.

 

[GaryE]

The usual culprit is M. marinum. It's common and deadly, but usually slow acting unless there is an outbreak. No one wants to talk about because humans can get it from their fish, if you have an open cut and are immune compromised. It's bad for business, that one.

I had to learn it - I caught it. 6 months of antibiotics worked, though I will always test positive for tb because of the antibodies.