Cory Seems Unwell

[BeezerGeezer]

Since Friday he has been hiding in a corner. He appears to have made a small well in the substrate and is resting there. Has also turned dark in colour. His little buddy is hanging around nearby and whenever one of the other fishes heads towards the quiet one, he steams in and parks himself over him. There doesn't appear to be any external sign of sickness. The tank parameters are OK, pH 7, Nitrite 0, Nitrate around 40, ammonia between 0 and 0.25ppm, all as the last tank. I moved all the fish to a new tank last Sunday, gone from 100l to 450l, same plants but fresh substrate. Same stuff as in the last tank, Columbo Flora base. Used the same chemicals to prepare the water, temperature is up a little bit from before, originally 28, now 30. Apart from the extra space, everything else should be as it was before.
Any suggestions gratefully received.

 

[Harlequins]

What type of cory is it?

The ammonia needs to be zero - readings of 0.25ppm is not good... Unless its a sterbai your temperature is far too high for the average cory, which ranges from 22- 25 degrees.

Ideally they need more tank mates, corys are social fish and need minimum 6, in that size tank you could have a good size shoal.

 

[Akasha72]

drop the temp for a start. Cories like it cooler - around 25ish

 

[BeezerGeezer]

Ok, temp can be lowered, however they share the tank with discus and they don't like it below 28. Both corys are Julii. Why would only one be affected? I do plan to enlarge the shoal. I've never been able to achieve a reading of 0ppm ammonia, perhaps it's the test kit? It is in date. I used the media from the old filter so it should be cycled. I've got under 40" of fish in 100 gallons, filter is an EX1200 so ammonia shouldn't be an issue.

 

[Akasha72]

28 is still a little too warm for cories. They'll withstand that short term - like if you need to higher the temp to combat itch - but long term they will be lethargic and unwell.

Maybe you need to look at the stocking if the Discus need that higher temp. Maybe keeping discus and cories in the same tank isn't going to work

 

[BeezerGeezer]

Perhaps you're right, but all were fine in the smaller tank which was at 28. When I first introduced the discus the temp was around 26. They spent all their time cuddled up to the heater. I turned it up to 28 and all were fine. There is a lovely tank at my lfs with a good mix of fish including discus and corys, I'll find out what temp they keep theirs at. However, I think there is more going on than just temperature issues. The other cory is still pretty active, the quiet one is coming out for food and upon examination looks and behaves fine. Is there any likelihood that they are trying to start a family, so to speak?

 

[N0body Of The Goat]

As said earlier in this thread, I suspect the issues here are related to the excessive temperature and the apparent lack of a social group of the catfish.

Are you sure they are Corydoras julii and not the often missold Corydoras trilineatus (which is a very temperate Corydoras like Peppered, found in the wild as low as 16C on offical record)?

 

[BeezerGeezer]

Right-ho Mr.Goat, I think you've hit several nails on the head. I checked out Google images and I think they are indeed mis-sold 3 liners. Also, the tank lights went out just after 10 so I did my species check with a torch. Quiet cory was out of his corner snooping round the tank quite normally. Would it be fair to assume it is suffering a confidence crisis? The new tank is quite sparse at the moment compared to the old one. Would it be ok to mix different species of cory? I'll go to the shop tomorrow and pick up some more. In the meantime I have turned down the 'stat on the heater.

 

[fluttermoth]

The new tank is quite sparse at the moment compared to the old one.

I think you've hit the nail on the head there!

They're in new tank, with not much cover, and there's not many of them. You and I know there's not a corydoras eating oscar round the corner, but they don't!

Would it be ok to mix different species of cory? I'll go to the shop tomorrow and pick up some more.

Same species groups are much better, if you can manage it, but all species of cory will shoal together to a certain extent. Certainly another species, if you can't get more three-lined, would be better than leaving them as a pair, IMO anyway.

In the meantime I have turned down the 'stat on the heater.

I'm sure that'll help too; in the long term if not right now.

 

[Harlequins]

Personally i would opt for sterbai's if you wanted to add more cories, the tri's life expectancy will be shortened by them living in a tank at that temp for long periods of time,whereas sterbais happily live up to 30 degrees...

 

[BeezerGeezer]

Ok, thanks for all the advice chaps and chapesses. Hopefully my local outlet will have the stock I require. My new light unit will hopefully be ready this week too, so I can add some more plants for the little tykes to hide behind.

 

[BeezerGeezer]

Visited the fish shop on the way home tonight and picked up a couple of Sterbs. It looks like a full on Cory love-fest now. I'll get a couple more later in the week, they look great as a shoal. Thanks again to all of you.

 

[Akasha72]

no problem. The more cories there are the happier they will be

Good luck with them