Need Help. Dying Cory Cats!!

adayton

AC Members
Jun 1, 2006
10
0
0
Hi all,
I have a 37 gallon heavily planted tank. All my fish are super healthy and my water chemistry is pretty normal:
Ph 7.0
kH 3 (how many drops it takes to change the test water from blue to yellow)
Nitrate 0
Nitrite 0
Ammonia 0
Phosphate (pretty low)
Temp: 80

I am not a newbie and this tank has been stable for about 1 and a half years. I have never had any problems with Corys and have always kept numerous ones in my previous tanks. For some reason every time I add any of them, they die usually within a couple days. My wife says she noticed a couple dart to the surface and bonk their head on the glass canopy. Could this be the culprit? My water level is too high relative to the canopy and they are killing themselves? None of the fish in the tank seem to have ever pestered them. I have 2 clown loaches, a electric blue Jack Dempsey (he is pretty tame), an Angel fish and some various tetras. I have now flushed 5 different Corys. They are some of my favorite fish and I can't understand why my tank is their doom. Any help or similar situations extremely appreciated.
 
How much space is there between your canopy and your water??
 
They could be feeding on some bad algae or something.

I had black hair algae one time. Immediately got rid of it.
 
Hi all,
I have a 37 gallon heavily planted tank. All my fish are super healthy and my water chemistry is pretty normal:
Ph 7.0
kH 3 (how many drops it takes to change the test water from blue to yellow)
Nitrate 0
Nitrite 0
Ammonia 0
Phosphate (pretty low)
Temp: 80

I am not a newbie and this tank has been stable for about 1 and a half years. I have never had any problems with Corys and have always kept numerous ones in my previous tanks. For some reason every time I add any of them, they die usually within a couple days. My wife says she noticed a couple dart to the surface and bonk their head on the glass canopy. Could this be the culprit? My water level is too high relative to the canopy and they are killing themselves? None of the fish in the tank seem to have ever pestered them. I have 2 clown loaches, a electric blue Jack Dempsey (he is pretty tame), an Angel fish and some various tetras. I have now flushed 5 different Corys. They are some of my favorite fish and I can't understand why my tank is their doom. Any help or similar situations extremely appreciated.

Your tanks is too old to have no NitrAtes, are you sure your test kit is good? I'm not very familiar with heavily planted tanks, so maybe the plants are using the ammonia (fish waste) and you have no nitrAtes.
 
:dance2: I could be wrong, but your tank seems to be pretty heavily stocked. JDs get pretty big, and can be aggressive. I would think that even heavily planted a 37g might be too small for a JD and an angel. Maybe someone is pestering the cories when the lights are out? ...just trying to help...... good luck!
 
What kind of substrate do you have and how often do you vacuum the gravel?
 
Hi,
The gravel is standard pea gravel mixed in with flourite. As for the stocking, I will eventually get a bigger tank but for now the size is fine relative to the size of my Angel and EBJD. The next tank jump will probably be in the 90 gallon range and that will happen basically to accomodate these two. I don't think it is a bullying issue. Both the Angel and EBJD are pretty mild mannered and I have not witnessed either one of them harrassing anyone other than each other. I was thinking perhaps it could be a toxin in the algae on the subtrate. Since the tank is pretty well planted there are pockets of algae and plant debris in the corners. I was always told NOT to vaccum the gravel when dealing with a planted tank. Should I try and clean up these mucky spots?

-A
 
AquariaCentral.com