PlanetCatfish.com

Hi,

i have a shoal of Corydoras aeneus, and one mysteriously died on Thursday.

The water parameters are:

Temp: 26c
pH: below 5.8 (strips dont test lower)
dh: 3
Amonia: 0
Nitrate: 0
Nitrite: 0

Fed vegatable flakes, standard flakes and catfish tablets twice daily.

Here are some pics of the fish and their set up. If unclear, the scutes at the rear end of the fish appear to have lifted up, and are the spikey things that are pretruding up from the body. The fish is 36mm SL and 42mm TL.



Thanks


Harry

sorry, forgot to add, the filtration is peat and ammonia remover (external Fluval 204)

sorry, more i forgot to add:

Water change every two to three weeks


Tank:
100cm x 30cm x 50cm
Sand substrate
Two large bogwood pieces, and five small round stones
Other tank mates:

1
5
1
2
1 Clown Loach (Chariobotia?)
11 Samll Tetra
2 Ram

Been set up since January

Last week, I had to use anti fungal medication for the Serpae tetra. Nothing at the time was noticable on the cory.

Thanks
Harry

The thing sticking out of the caudal peduncle could be a fluke but the picture is not clear enough to see properly. You should be able to see with a magnifying glass or better, a microscope.There is obviously serious fin damage although this could be post mortem.

Your tank looks strangely cloudy and appears to me to be newly set-up. Are you sure it's fully cycled? You need to buy some decent test kits, strips just aren't good enough for the job.

As always, a good regime of properly conditioned water changes will nearly always help, although if you do have a parasite infestation you will have to treat it.

Ive only got photos of pictures of when it was newly set up, and the water was cloudy as I'd just finnished plating. Its been running for around three months now, and it has fully cycled. Since then, the plants have started spreading out and the woods have tanined (?) the water a lovely yellow, black water colour.

I have proper test kits for ammonia, nitrate and nitrite. When I take the Cory into the LFS tomorrow, I'll pick up some better test strips. I'm only using them at the moment as I had some in the cupboard and the others had run out.

There wasn't any fin damage when it had died - its been sitting in the fridge for the last two days and has probably been knocked about a bit.

Thanks for the help,

Harry

How long has the ammonia remover been in the filter? after a while these products dump back into the aquarium what they have taken out.

pH 5.8 or lower - you really need to find out how much lower it really is...

Can I take the low pH to indicate that you are using RO water? If so, what are you adding to it to keep the pH stable?

Changing water every 2-3 weeks is quite possibly not often enough...

And we really need to know what your ammonia, nitrite and nitrate levels _REALLY_ are - nitrate of zero is "not right" - it essentially means that your filtration is not working.

--
Mats

I am far from an expert. But I believe aeneus come from about a 7 pH environment. I would be very suspect of having them in water that is 5.8 or lower. In addition, corys don't really like high nitrates. Given your wc regimin and minimal plants in the tank, you should be showing some level of nitrates if you are truly cycled. I would get a good liquid test kit because strips are basically a waste of time and money.

I think that the low pH is causing stress and increasing susceptibility to illness. pH fluctuations might be occurring as well. Check your pH a few hours after lights out and then test again around mid-day.

I've used a more accurate test kit as I wasn't convinced by the results, and the nitrate is 10-12 ppm. The water isn't RO, it just has peat filtration and new (ish) bogwood releasing its tannic acids. The LFS where I bought the Corys from kept them in water of 6 pH. I went to a specialist today to talk over what has happened, and the situation has pretty much been resolved in terms of the water etc, but the death is still a mystery. Their best guess would be a bacterial infection, as the investigation turned up no answers.

The ammonia remover has been in 3 months, it reccomends to be replaced every 9 months on the box.

Thanks for everyones help,

Harry

Harry,

Where do you live, more precisely than "South East England"? A town/village and country would be good.

Is the water you use rain-water, or tap-water? For nearly all of South-east England, the water is quite hard, and I don't actually believe that a small amount of peat or some bog-wood will achieve 5.8 or lower pH. So either the pH test is not accurate, or you aren't using tap-water - or you live somewhere where the water is quite soft.

--
Mats

I live in a small village, the nearest large town would be Windsor. I use tap water, with comes out of the tap at 8. Myself and the people in the LFS were very surprised by the huge drop in acidity and dh from the bogwood and peat. I've had the water re-tested accurately, and they are definately below 5.8. This weekend, I'm hopefully going to find out the exact measurement, and if not, my Chemistry teacher will let me test it with the indicators in school to get a definate figure.

Thanks again for the help,

Harry