I change about 30-40% of the water once per week. It’s not auto, or heavily planted.
Dead Carpintis
- Thread starter RTCfan86
- Start date
whatever it takes to keep nitrates below 20 ppm.. what you're doing should be right at that threshold ..
Those water readings seem suspect. A cycled tank should show at least some nitrate.
You mention that you cycled the tank with a few neons, and that the carpintis has been in it for 9 days. Was the rest of the current stocking introduced at that time as well? A tank that is cycled with a few small fish like neons is supporting a bacterial population that can subsist upon and metabolize the relatively small amount of ammonia that those few small fish produce. It is "cycled" but that doesn't mean it harbours a colony of bacteria sufficient to suddenly handle the ammonia output of a vastly and abruptly increased bioload. Going from a few neons to four much larger fish increases the bioload by probably a factor of 50 or more. Even if the original cycled media came from a tank that had a much larger biomass, equivalent to the biomass you now have, the bacterial population would immediately begin to drop due to a lack of sufficient ammonia to sustain this large bacterial colony. You would actually be reducing the total amount of beneficial bacteria rather than increasing it. Then, when you add the big fish, you experience a sudden ammonia spike until the bacterial population increases to utilize the suddenly increased ammonia output.
The bacterial population is not like a coat of paint that you slap on and call it good. It is a living system, which grows and dies off as the food supply increases or decreases...and it is more important to your success than the fish.
You mention that you cycled the tank with a few neons, and that the carpintis has been in it for 9 days. Was the rest of the current stocking introduced at that time as well? A tank that is cycled with a few small fish like neons is supporting a bacterial population that can subsist upon and metabolize the relatively small amount of ammonia that those few small fish produce. It is "cycled" but that doesn't mean it harbours a colony of bacteria sufficient to suddenly handle the ammonia output of a vastly and abruptly increased bioload. Going from a few neons to four much larger fish increases the bioload by probably a factor of 50 or more. Even if the original cycled media came from a tank that had a much larger biomass, equivalent to the biomass you now have, the bacterial population would immediately begin to drop due to a lack of sufficient ammonia to sustain this large bacterial colony. You would actually be reducing the total amount of beneficial bacteria rather than increasing it. Then, when you add the big fish, you experience a sudden ammonia spike until the bacterial population increases to utilize the suddenly increased ammonia output.
The bacterial population is not like a coat of paint that you slap on and call it good. It is a living system, which grows and dies off as the food supply increases or decreases...and it is more important to your success than the fish.
No, the neons went in the tank 7/1, and after a few weeks, started introducing more fish, up to 5 small cichlids in addition to the neons, who were shortly after moved. Some cichlids have come and gone due to aggression, and have had a successful spawn in there too. But I never saw a spike in the ammonia after the first one, and never lost a fish until this one, which made me think of a fish problem vs a tank problem. Thanks for that very detailed information, very helpful.
Okay, that's good to hear. Nevertheless, it doesn't explain how your nitrates could be zero. And it that reading is incorrect for some reason, I'd be cautious of the other ones (nitrite and ammonia) as well.
I just did a water change, so retesting now may be a waste of time, right? I could wait a few days and retest.
Well, if you did a 100% change...and if your source water has zero nitrate...then a zero reading might make sense. Otherwise, I couldn't resist the temptation to test again, just to see if I got a reading that seems explainable.
If you did only a normal partial water change, and if you don't have have some ultramodern whizbang gizmo that is 100% effective at removing nitrates (pretty sure that doesn't exist!) then, yeah, do the test. If it reads zero again, something is screwy somewhere and may help point you in the direction of an explanation of this fish death.
Think about it. Whether your tank is cycled or not, how could there be fish living in it...eating, metabolizing, excreting waste...and yet all three parameters (ammonia, nitrite, nitrate) register as zero? Just doesn't add up.
I get what you’re saying. I meant I just did a water change right now, after yesterday’s test. I’ll test again now though and post a pic.
