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CO2 & dead fish

cubist

Seedling
Joined
23 Mar 2009
Messages
4
Help me if you can.
Have a newly matured D-D 24g cube set up as a planted tropical tank.
ph 7.6, temp 26c, ammonia o, nitrite 0, nitrate 0.

CO2 is by the Tetra CO2-Optimat system which i have been dosing at the rate of 1 x diffuser tube full per day.
The guy in the shop said i should do this during daylight or tank illuminated hours which is what i have been doing.
Everything was certainly fine doing this with the Danios that i put in over a week ago and they are still ok.......BUT i put in 5 x Neons yesterday and left them to it for 24 hours without CO2 dosing. Today at 12 noon when the lights came on the tank i started the usual CO2 dosing as previosly described. Within about 3 hours (approx) i noticed a dead Neon and then another 2 in the next hour......they looked to be gasping at the surface & breathing very quickly before dying. The last one is on the way out as i write and i dont have an aerator to help with oxygen.

DID CO2 KILL MY FISH ??
DID I DO RIGHT IN DOSING THE CO2 WHILE THE TANK IS ILLUMINATED ??
I have read the Tetra leaflet that came with the system but to be honest i think the bit about dosing times is very badly written and confusing!

Your responses and thoughts would be appreciated.

Peterg
 
I would be very surprised if it was the CO2, that system isn't very efficient so you probably wont have had much co2 in the water. Fish can last a surprisingly long time in high co2 (I had an otto in water for 12hrs that must have been near 50-60ppm CO2).

Neon's are known for being tricky to get started, so it probably was just a bad batch.

Sam
 
I'd have to agree with Sam, neons can be very tricky.

You do say your tank is newly matured, how many weeks has it been from the start btw?
 
As Sam says it's a very ineficcient CO2 source so in my opinion it's extremely unlikey to cause the deaths. I think you should be looking elsewhere for the problem. Have you tested the water?
 
Thanks for responses so far.

To confirm: All relevant water parameters are "zero".
Tank has been maturing for about 3 weeks.

I never knew that neons were so sensitive but i can't think what they are reacting to.

Peterg
 
Sorry, didn't read the original post well enough to realise you stated the water perameters :oops:

I've had "bad batches" of neons before and lost quite a few. Have you got any recourse with you're LFS? Do they give any guarantees on their livestock?

With regards to the other question (when to dose CO2) you're right to add when lights are on or preferably fill cannister an hour before lights up. Although with the tetra plant CO2 Optimat system it's not going to make a lot of difference in my opinion.
 
Neons can be fragile at the best of times, especially with water on the alkaline side of things. That's made worse by your tank having not really matured yet. I'd either go with a hardier tetra, or wait a while before getting more neons.
 
Simon D said:
Sorry, didn't read the original post well enough to realise you stated the water perameters :oops:

I've had "bad batches" of neons before and lost quite a few. Have you got any recourse with you're LFS? Do they give any guarantees on their livestock?

With regards to the other question (when to dose CO2) you're right to add when lights are on or preferably fill cannister an hour before lights up. Although with the tetra plant CO2 Optimat system it's not going to make a lot of difference in my opinion.

What's really come to light through this post is that neons are so finnicky. I've kept them before without problems. Maybe its the ph is too high for them. Problem is my tap water is ph7.6 and ai dont particularly want to start chemically changing it.

Peterg
 
gratts said:
Neons can be fragile at the best of times, especially with water on the alkaline side of things. That's made worse by your tank having not really matured yet. I'd either go with a hardier tetra, or wait a while before getting more neons.
Sounds like good advice to me, thanks.
 
I also use the Tetra CO2 system ,but in a small and established tank.
The only livestock i have are Ottos, and the supposedly very sensitive Crystal Red shrimps, and i recharge my tube 2/3 times a day, plus easy carbo, and no livestock problems.
I would agree with whats been said, get your Ph to 7, and are you satisfied the fish were ok to begin with.
Good luck.
 
Without re-iterating whats already been said, the symptoms and stages the neons showed are classic signs of ph shock, I used to work in the aquatic trade and unfortunately saw with some species including neons how this could affect them quite reguarly despite a delicate acclimatisation process. Also you should consider where in the world these fish came from and how they were reared, as the practise in some countrys is to use high levels of treatments to ensure maximum amount of fish are grown to a sellable size which results in a low to no immunity to stress/parasites/disease etc which can all contribute to fish deaths.
 
It's a problem with many mass produced fish, especially those that are considered staple community species. Cardinals were always more finicky than neons, but because of the mass production techniques neons tend to be quite problematic. If you can buy stock that's been quarantined and have been in the shop for a few weeks you should be OK, but many LFS get boxes full of neons delivered (including dead ones) put them all in their show tanks and then sell them the next day. It's allways interesting returning to the shop after your's have perished to see if how many of the shop's stock have survived (if any!), obviously taking into account a proportion that have been sold.
 
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