LOSING SOME OF MY CORY'S

[Ray.M]

Hi,
I have a community Discus tank and I have been losing some newly acquired corys in recent times. The symptoms are always the same.
Firstly the corys tend to quickly dart to the surface.
Next day they dart to the surface but seem disorientated and spin and flip.
Sometimes they lay on their side when they get back to the bottom.
They soon die after this point - maybe the next morning.
I seem to loose octocinclus at the same time.
There does not seem to be any physically visible issues.
All my other fish seem OK. Peppermint BN, Whiptails, Rummy noses & Discus
Although I do 2x50% water changes per week my phosphates (1mg/l) & nitrates (25-50mg/l) always seem to be on the higher side.
Can anyone help to identify the cause - I feel it is a water parameter.
Thanks,
Ray

 

[JackGillett]

It maybe the water, it maybe the batch. What oxygen is in your tank? That may be a problem, but then it could be temperature. Discus like high temperature, corys like low temperature. What is your tank? And what are the corydoras?

 

[bigbird]

Hello,

Sorry for your loss, could be old tank disease.
Agree with Jack, what size tank, what filters do you have, do you have aeration, how many fish do you have, how old is the tank, temp of the tank, feeding schedulle , what is the PH etc ? all this will help with diagnosis. cheers jk :thumbup:

 

[Ray.M]

Thanks,

I am currently treating for white spot so my temp is high 32C.
I usually have the tank at about 28C.
The tank is 300L
Filters - Eheim media - 2217 + 2075
Ph 7
Fish
5 discus
4 peppermint BN
1 whiptail
18 Rummy noses
5 cardinals
2 clowns
4 corys (now)

Thanks,
Ray

 

[Ray.M]

In relation to oxygen I am running a Schego M2K3 with two airstones.

 

[bigbird]

in my view......way too hot for corys......they do not like hot water. What type do you have, as there are only some like sterbai that might be able to tolerate warm-hot water. cheers jk :thumbup:

 

[Ray.M]

Metae currently. the earlier ones I lost were Julii.

 

[bigbird]

they usually like 24-26C. Might be lack of oxygen and heat stress. how long have you had the tank for and when did you add fish last. the reason I ask, is that in a tank that has been set up for a while, the fish in this tank get use to the water and any news ones you add, get stressed and are unable to adjust and then pass away. cheers jk :thumbup:

 

[Ray.M]

I have had this tank for about 8 years but I have only had the tank at about 28C for the last couple of years.
I can see from what you are saying that it may well be the issue and I really appreciate your input.
I put the other cory that was showing similar symptoms and the ottocinclus in my QT tank at a lower temperature and they seem to be recovering.

As a side note I noticed that the bottom half of their tail fin appears to 'wear' away (all my corys). Is this caused with the gravel base I have ?

Thanks
Ray

 

[JackGillett]

That's your problem. Bigbird has explained it, I wouldn't keep anything but Sterbai corydoras in 28'c water, and no corys in 32c water. Personally I don't agree with keeping corydoras with discus because as you've stated the temp is up to help health problems, and that can be quite common

 

[Lornek8]

I have had this tank for about 8 years but I have only had the tank at about 28C for the last couple of years.
I can see from what you are saying that it may well be the issue and I really appreciate your input.
I put the other cory that was showing similar symptoms and the ottocinclus in my QT tank at a lower temperature and they seem to be recovering.

As a side note I noticed that the bottom half of their tail fin appears to 'wear' away (all my corys). Is this caused with the gravel base I have ?

Thanks
Ray

How often do you clean the gravel?
Are any of the other bottom dwellers showing similar conditions?
Sometimes this can be due to bacteria levels increasing if the substrate is not cleaned often or thoroughly enough. This can be especially exasperated in a warm tank as the higher temps speed the growth of bacteria and the breakdown of leftover food. This can be a common problem with discus as they are pretty messy eaters. The heat could additionally compound the problem in the corys as it could be creating additional stress which might be why other fish aren't showing signs.

 

[Ray.M]

I tend to clean the gravel every couple of weeks as a minimum, sometimes weekly. It seems likely the high temperature is the real issue. I have a whiptail who's bottom tail fin is all the way to the bone and the ottocinclus show similar signs. The peppermint bristle noses are fine.
Although I have the heater set at 26 (and is essentially off) I can not get the temperature below 30 in summer.
I assume the lights, filters & UV must be adding to the heat load.
Is there any practical way of being able to lower the temperature by a few degrees ?
This post has been a great help to me and I would like to thank all of you that have participated.

Ray

 

[JackGillett]

The high temp may also bee the cause of the tail problem. Lower the heater temp, cool water change?
i would think about re doing the stocking i this is a consistant problem

 

[Squirtle =)]

Not sure about the temp issues? I have sterbai( think thats right) in with my discus at 30C and they are always laying eggs and swimming around the tank like a school of rummies :S I do think the sterbai can handle higher heats but?

as for lowing the temp, I freeze fish tank water in big 2L bottles then in summer I place them in the tanks that go over 30C lowers the water down to 26-28 completely safe for the fish too as its not an instant drop nor does it change the PH etc as its the same water

 

[phoenix44]

Do you have a lid on the tank? Like a glass sheet?

Them coming up for air is pretty common but if they knock them selves on the head....