Do corydoras catfish exhibit rolling or flicking as natural behavior?

[bereb]

I've noticed my corydoras exhibiting this behaviour where they flick and almost roll down at the substrate, and it's happened quite a few times since I introduced them to the tank.
It seems to be substrate-specific, as I've not seen them do it against plants or any of the tank equipment, which got me thinking - is this a form of play, or are they trying to kick up the substrate to dislodge any food particles that might be buried?

The corydoras appear to be perfectly healthy, no visible signs of illness or stress, and it's only them doing this - not the rasboras in the same tank.

[coltin]

I'm inclined to think this isn't normal behaviour and could be indicative of a disease. To better understand what's going on, it'd be great if you could provide clear pictures and a video of the corydoras exhibiting this behaviour.

If you could upload the videos to YouTube and then copy and paste the link here, I'd appreciate it. When recording with a mobile phone, please hold it in landscape mode.

[bereb]

I'm inclined to think this isn't normal behaviour and could be indicative of a disease. To better understand what's going on, it'd be great if you could provide clear pictures and a video of the corydoras exhibiting this behaviour.

If you could upload the videos to YouTube and then copy and paste the link here, I'd appreciate it. When recording with a mobile phone, please hold it in landscape mode.

I'll get those videos up on Youtube as soon as I can, thanks for the advice coltin.

[Clack]

Similar thing happened with my corydoras, ended up worming them after posting on here and getting advice. Never seen that behaviour before, and it stopped after the worming treatment.

[bereb]

I'm inclined to think this isn't normal behaviour and could be indicative of a disease. To better understand what's going on, it'd be great if you could provide clear pictures and a video of the corydoras exhibiting this behaviour.

If you could upload the videos to YouTube and then copy and paste the link here, I'd appreciate it. When recording with a mobile phone, please hold it in landscape mode.

I'm keeping a close eye on these corydoras - they're currently in quarantine with some new hengels rasboras. I've been reviewing the footage and I think I might have missed something at 0:29. Initially, I thought it was just substrate, but it's possible that's the start of ich.

The conditions in the tank are as good as I can make them - I'm doing 50-60% water changes every week. The tank's 105l, planted, and at 25 C with 9 dGH hardness. I've just done a second 10% water change to remove the salt I added for Saprolegnia fungus - 2 tablespoons per 20 litres. Also, I've noticed some of their barbels are quite short, but that was the case when I got them.

[Rampar]

They look fine in the video to me. One thing I did notice was the spots on that cory at 0:29. Not really sure what to make of that.

[coltin]

The rubbing on the substrate is likely an external protozoan infection. If the fish has white spots, they usually rub on objects, but in this case, it's hard to tell if the spots are white spot or just excess mucous.

A possible treatment for white spot is to raise the water temperature to 30C (86F) for at least 2 weeks or 1 week after all the spots have gone. No chemicals are needed, just warm water. When increasing the temperature or using medication, make sure to increase aeration and surface turbulence to maximise oxygen in the water.

If the spots don't change after a week, it's likely not white spot. White spot parasites drop off the fish after a few days and reappear a few days later, often in different places. If the spots remain unchanged and the fish are still rubbing, it could be an external protozoan infection like Costia, Chilodonella, or Trichodina.

In that case, you can treat with salt. Use rock salt, swimming pool salt, or non-iodised salt at a dose rate of 1 heaped tablespoon per 20 litres of water. If there's no improvement after 48 hours, you can double the dose rate. Keep the salt level like this for 2-4 weeks, but be cautious of kidney damage, especially in fish from soft water.

To add salt, dissolve it in a small bucket of tank water, then slowly pour it into the tank near the filter outlet over a couple of minutes. When doing water changes, treat the new water with salt before adding it to the tank to maintain a stable salt level and minimise stress on the fish. After treatment, do daily 10% water changes for a week, followed by 20% water changes, to slowly dilute the salt out of the tank.

[bereb]

I'm inclined to think this isn't normal behaviour and could be indicative of a disease. To better understand what's going on, it'd be great if you could provide clear pictures and a video of the corydoras exhibiting this behaviour.

If you could upload the videos to YouTube and then copy and paste the link here, I'd appreciate it. When recording with a mobile phone, please hold it in landscape mode.

I'm grateful for your input. I'm a bit concerned that 30C might be quite stressful for my corydoras over a two-week period - do you think they'd be able to handle it?

I'm still in the process of removing the salt from the water, so I won't be able to consider using heat or other treatments for about a week or so.

[coltin]

Corydoras should be okay at 30C for 2 weeks. They might get a bit stressed, but it's a relatively safe temperature for them. Just make sure to keep a close eye on them and maintain good water quality.