Sick Cardinal Tetra - Help

[ToxicAngel]

Hi All,
 
I set up my tank about 6 months ago and haven't had any major issues till recently. I had 7 cardinal tetra and then 1 just disappeared about 2 weeks ago and now another looks ill. He's gasping alot and hiding all the time. He seems to have a fuzzy gray patch on his belly, hopefully you can see from the picture:
 

 
I do ~ 30% WC once a week and test the water just before. I've not seen any ammonia or nitrite since I cycled the tank and never get more than 5ppm nitrate. Could fluctuations in pH have caused this? I had added some coral to my filter to increase the pH as it was very acidic (5.2) but it then when too high (7.5),  I was aiming for 6.5 so I removed some when I last cleaned the filter (using tank water).
 
Does any one now what it could be or if there's any medications I could use? I have shrimp so it would have to be copper free.
 
Thanks in advance
El

 

[Asteria]

That grey patch on the belly is normal in cardinals. I have 10 and they all have it.

It's most likely stress from the sudden ph change.
The pH should be handled delicately. A sudden change can put the fish into shock.
My suggestion is to leave it. Don't take out any coral or add any more.

 

[Byron]

I would say from that photo that there is something wrong.  I am not much good on disease issues, so I will not guess.  But I really do see a problem with this fish.
 
On the pH, it would have been fine at 5.2 for cardinals, though shrimp may have issues with the lack of mineral (I assume the water is soft, GH is the more significant thing here).  I found that using crushed coral (I experimented a lot with this and other buffering methods) sent my pH sky-rocketing with just half a cup in a 115g tank.  You certainly do not want the pH above 7 for cardinals, and in the low 6's as you planned will be better.
 
Byron.

 

[sparrow]

his belly looks ok to me as i keep cardinals and they are similar looking bellys. the red looks a little fuzzy in that area usually. my ph is 7.2 as thats how it comes out the tap. and i never had any problems. often fish can adapt to different ph levels so as long as its not extreme they will be ok. most likely the fish is stressed my the ph change. just leave the tank alone and dont intefere. he may get better on his own. if you try to interfere too much he might get stressed out more.

 

[Byron]

I'm not sure we are all looking at the same photo.  If you click it to enlarge it, there is clearly a couple of black patches that appear to be from inside the fish. What this is I do not know, but it is not normal for this species.

 

[ToxicAngel]

Thanks for the responses guys. Unfortunately I lost him yesterday, of the 5 remaining I think one of them may have the same issue. He's not showing the fluffy/fuzziness on his belly yet and he still being sociable with the others but he is continuously opening and closing his mouth. I going to try some Pimafix anti-fungal fish remedy. I've heard some people use this as a matter of course so figure it can't do any harm. Fingers crossed.

 

[sparrow]

Im so sorry this has happened. maybe ask at your fish store as it may be bacterial in which case melafix would be better. As far as im aware fungal r usually on the outside of the fish but dont take my word for that. Also i cant see the black spots perhaps my screen isnt as good quality as yours. Perhaps he has worms? is there any swelling? Gasping suggests an oxygen issue or possible injury? is there enough movement on the surface of the water?

 

[ToxicAngel]

Thanks sparrow. I'll see what they say at the store but I'll probably get the melafix as well and try that too. I don't think it's an oxygen issue as none of the other fish are gasping and the only one who goes to the surface is my pearl gourami.

 

[Byron]

Just a couple of general comments, as again I do not guess about disease.
 
Increased respiration is common to almost any disease/problem.  So this alone cannot be of much use as to the cause.  Whe the fish is so severely stressed as it is by any disease, it needs more oxygen and naturally respirates faster; sometimes they remain near the surface where oxygen is generally more dense, or in a filter flow.  But it is a sign of a problem, though not necessarily one involving water quality (O, CO2, ammonia, pH, etc.).
 
Second, don't guess and start using medications.  No matter what medication you use, in most cases it will be stressful to the fish, both the healthy and the sick.  The wrong or inappropriate medication can make things even worse.  I know, I've been foolish in the past and lost fish from doing just this.  Do your best to ID the issue and then use the safest but most likely successful treatment.
 
As this seems confined to the cardinals, check with the store and see if those they have left are showing this same symptom.  Check the fish yourself in the tank, and ask them too.  If they are honest, they will tell you.  Cardinal tetra are sensitive fish; I know of a store near me that guarantees all their fish for a week or whatever it is--but they will not guarantee cardinals.
 
Byron.