HELP PLEASE !!! new tank - fish dying!!!

[haddock]

I have got a new 60 US gallon tank which I set up a week ago - I'll give you a run down of exactly what I did, sorry its a bit detailed:

1) washed sand and added to tank
2) added water, pre-treated with aqua-safe
3) added plants
4) put cyle (bacteria) into biological filter in fluval 404 (second hand filter- but cleaned well)
5) turned everything on - heaters, filter, lights.
6) waited a week - water crystal clear.
7) tested water (two days ago)- PH 7.2, ammonia 0.24, nitrate and nitrite zero, temp 27oC.
8) I bought 3 small panda corrys and 6 small harlequin rasbosoa, which according to my LFS would be fine for cycling the tank.

So yesterday evening, one of the harlequins was swimming slowly, in circles, looked quite hollow, had red gills and bulging eyes!! It died shortly afterwards .
Now today another harlequin looks like that too!

I have just tested my water - ammonia 0.25, Nitrite 0.25, Nitrate 0.5
I have just done a 20% water change, otehr than that I have NO idea!!

Help would be appreciated.

ps there appears to be a "cool" smilie randonly appearing in my post - just for the record, this is not cool....

 

[WILDER]

Becuase the tank isn't cycled, red gills are from high nitrates, all i can suggest is a water change, you could lose alot of fish due to the cycle, also i would add an airstone for extra aeration if you have one, do you have another muture tank.

 

[haddock]

In the time it has taken me to write the above post, the harleqin has died.

 

[haddock]

Wilder, thanks for your reply - no I don't have any other tanks unfortunately.

So, do you think that 0.5 nitrates is enough to start killing fish - I thought that was quite low?

What about the bulging eyes and I forgot to mention that the fish's mouths were locked open. Do you think this might be a disease?

 

[WILDER]

Sorry, but they are very sensitive fish to water quality, do you have another mature tank, you could take some filter media out of, if not i would do a water change immediately.

 

[WILDER]

Bulging eyes probably due to the water quality, and the locked jaw sorry them fish are going to die, as there is nothing you can do for them.

 

[WILDER]

Can you list the fish you have in the tank.

 

[haddock]

Wilder,
I have 3 small panda corys (seem to be fine) and 6 (now 4) harlequins. I was waiting until the tank cycled before adding more.
Maybe the harlequins are too sensitive for a new tank then.
You live and lean.
If the harlequins all die then I could add some more panda corys - what do you think?

 

[WILDER]

The panda corys are very senstive to they need excellent water quality, for now i would do a water change, you can't add salt as you have the corys.

 

[haddock]

OK, no more corys then. I have just done a 20% change - do you think that is enough?
Thanks loads for your help by the way.

 

[FishEnthusiast]

My suggestion would be to wait until your ammonia is 0, your nitrites are 0 and you have measurable nitrate before you add any more fish. After you are cycled you will have lots of choices as you have a nice sized tank. Make sure you add fish slowly, 2 or 3 a week. That is what I did after my cycle was done, and I have had no fatalities.

 

[haddock]

Fishenthusiast,
Thanks for your reply - can't wait to be fully cycled - I didn;t expect to start killing fish quite so soon!

 

[WILDER]

Yes that water change is fine for now, keep an eye on fish and water stats, as you can tell when they look uncomftable then it's time for a water change, or do a few small water changes daily, so the fish don't suffer to much, also don't over feed cut down sligly while your tank has cycled, good luck.

 

[black angel]

sorry to correct you wilder but high nitrite and not nitrate is the usual cause of fish death along with ammonia.
the fish you chose do not do well with cycling and are quite delicate. if you need more fish to cycle with then danios are much hardier.
what did you use to clean the tank with? any residue from detergents may still be around and how did you clean the filter out?
the bulging eyes and open mouths suggests to me that something is poisoning the fish.

 

[haddock]

Black angel,
I didn't clean the tank, I just wiped it with a clean dry cloth before filling it up - should I have cleaned it? I cleaned the filter by taking it apart and washing eveything with boiling water. I scrubbed all the parts with a test tube brush.
I didn't dechlorinate the cleaning water - what would chlorine poisoning look like?
Fingers crossed I can keep the remaining 4 harlequins alive, if not the I will take your advice and get a few danios.