panda corys mystery illness

[jaybravo]

Hi folks

I registered here in the hope of finding a solution to my problem with Panda Corys. I've had some since I got my aquarium about 18 months ago and they seem very happy with the conditions. They feed well and are not bullied, have lots of places to hide etc and the water parameters are good. The problem I am having is that nearly every time I clean the gravel (with a siphon) one of them invariably gets sick and dies within a couple of days. Obviously I want to keep the tank clean of fish waste but it seems every time I try to clean (every 1-2 weeks), a little bit is stirred up and it makes them sick. I also have peppered corys and white cloud minnows, who are all thriving. Is there anything I can do to prevent this happening? I suspect it's a fungal illness because on one occasion a fish had white fluff on him and a bleeding fin. I've tried general medication for fungal infections with no joy, and I don't want to have to medicate permanently to keep them alive. Any advice is appreciated!

The temp is 23 celsius, pH 6.5 and I do weekly water changes. The water is hard but they seem happy with that provided the tank isn't stirred up.

[wrasse]

I wonder if the bit of white fluff is incidental, because I reckon this is more to do with a bacterial build-up in the gravel. And when you clean the gravel the trapped bad bacteria is released.
You might be overfeeding. Uneaten food trapped in the gravel could be the cause.
The pandas are possibly a touch more sensitive to this than the white clouds and peppered corys.
I think it would help the fish if you could increase the water flow and oxygen.
A long term measure would be to replace the gravel with silver sand about 2cm deep. The corys will love it, pushing their heads into the sand looking for things to eat. Food tends to sit on top of the sand rather than sinking in to it. And every so often you run your fingers through it to keep it fresh - the corys help with this too.
Short term medication I would use myxazin. Remove carbon from your filtration while treating the tank.

[jaybravo]

thanks for the reply. I too think it's probably some kind of organism living in the gravel as it's only when it's stirred up that they get sick. I will look into that medication and think about changing over to sand. I thought sand would be very difficult to clean but if all the dirt stays on the surface then it shouldn't be such a problem.

[DJ-don]

how big is your gravel?
if you have gravel which allows poop to ge through, maybe some ammonia gases build up and infect you pandas?
i found that panda cories are much more sensitive cories while peps are really strong and hardy

[jaybravo]

well the gravel is fairly fine and smooth but I'm sure it makes a pretty good trap for waste. I've tried cleaning it more often but obviously that puts the pandas at more risk of getting sick. Incidentally I had the same problem with norman's lampeyes so I put them in a different tank without gravel and a bare bottom for easy cleaning and they've been right as rain ever since, so I'm sure it's the dirt that's making them sick. The Pandas do seem particularly sensitive as the peppers are going from strength to strength - I just don't like them as much

Maybe I'll have to remove the pandas for a while and change the substrate to something more suitable before putting them back.

[RickE]

A silly question maybe, but are you sure the equipment you are using for the water-changes is clean and free from any chemicals and/or contamination?

[MatsP]

Can I just say that cleaning the gravel should not make the fish poorly - if it does, then you are not cleaning the gravel often enough and/or feeding too much - or there is some other underlying problem.

Water changes and gravel vacuuming should NEVER cause a problem in itself - if it does, there's something seriously wrong...

--
Mats

[jaybravo]

thanks Mat, I'm pretty sure it's both those things. I'll try to do a thorough clean and maybe use some medication to be on the safe side.

[MatsP]

medication to be on the safe side.

I think that's a bad idea. Unless you have very specific targets with the medication, it's probably little point in medicating against something that you don't know what it is. In my experience, fish medications that actually really cure things are strong enough that they also have side-effects. The exception is parasite medications, which are in my experience fairly harmless to fish but effective on what they are supposed to affect, but I doubt that's what you've got problems with.

Clean water is a good "cure" for most illness.

--
Mats