Dead fish

[ardane]

My tank is fully cycled and has been for at least 4 weeks

Ammonia 0
Nitrites 0
PH 7.5
Nitrates 5

I change about 20% of the water weekly

Since stocking my tank I have had 19 fish die, I appreciate that the fish that helped cycle the tank will have a reduced lifespan but is that many fish in 8 - 9 weeks normal?

Some of the fish have looked unwell before the end and a Gourami was nipped a bit

The fish have been bought from 3 different lfs' and there doesn't appear to be a pattern

I'm going to the lfs tomorrow to get the water checked, any advice is appreciated

 

[Dragonslair]

Your nitrates levels seem quite high. It does sound as though the fish have succumbed to new tank syndrome.

 

[ardane]

I think you are right about the new tank syndrome (lesson learned!! and I regret the fish had to suffer) but my nitrates are at the lowest level on my chart other than 0

 

[modernhamlet]

5ppm is high for nitrites, not nitrates. You have very good tank parameters. Maybe the testkit is bad? Definitely get the water checked at your LFS. Are you treating all the water (including during water changes) for chlorine/chloramine? Are the fish showing any symptoms before they die?

I'll leave the real troubleshooting to the experts, but those questions immediately spring to mind.

 

[ardane]

I agree with the nitrates explanation, I treat the tap water with stress coat and stress zyme, do I need anything else?

 

[Bol]

Your nitrate levels are fine. I wish mine were 5 ppm

Stress Coat should, in proper doses, take care of chlorine and chloramines, and most likely you wouldn't need anything else.

Personally, I'd just throw the Stress Zyme away, as I don't think it's doing much good (others will disagree). But, it shouldn't be doing much harm, either.

If they can, ask the LFS to test your water for chlorine and phosphates, if you think it's the water.

Some of the fish have looked unwell before the end

That's probably it. Sounds like it's the unhappy time to delve into learning about fish diseases, and how to identify and treat them.

 

[FanOFish]

The question is not what your tank readings are now but rather what they have been when you introduced all those fish.

If you have that many fish in a new tank they probably died of new tank syndrom even though now the tank is fine.