whats killing my tetras ?

[zkt]

30 gal
well planted
3 small gouramis
2 small red fin sharks
3 small red swordtails
2 small corys
3 neon tetras

added 4 more tetras yesterday
found them floating this am
this has happened befor
wtf ?

 

[Holly9937]

can you post your water parameters? Amonia, nitrite, and nitrate? Also, FYI, you will eventually need to get rid of one of the sharks, they get aggresseive as they get older/bigger (very much so with their own kind) and you will soon see them fighting, you can only keep one of those guys!!!

 

[zkt]

last week the nh4 was 0
nitrates were off the scale
dont recall nitrates
Ph was abut 7
10-4 on the sharks

 

[Holly9937]

nitrates were off the scale
dont recall nitrates

Which was nitrATes and which was nitrItes? Also, how often do you do water changes/gravel vacs. and how long has the tank been set up?

 

[zkt]

Nitrates >120
nitrites ?
If the algae looks like its about to take off I`ll do a partial, every couple weeks prolly.
Been up a few months
Lotsa light; south window 4 4ft flourescent tubes 16 hrs

 

[Aqualung]

How do you fit four 4' flouros over a 30 gallon?

Anyway, I would bet that the extremely high nitrates killed your tetras. You should be doing larger water changes, and much more frequently.

 

[Aqualung]

Also, you really don't need to leave your lights on for 16 hours a day. With that much lighting at 16 hours a day, plus sunlight and sky high nitrates.....you must have loads of algae? I bet my otos would love that tank (for the algae, not the nitrates)!

 

[Kasakato]

Ouch! Do water changes ASAP to get them to 20ppm.

 

[zkt]

Tank is 10x10x 63 inches.

I`m trying to boost the plant growth with co2 to the point where I see a reduction an nitrates.

 

[Kasakato]

Co2 wont do anything to nitrates. Only water changes will. Plants will use the nitrates, but the fish will die form them at that high of level.