Fish Died, No Reason Obvious.

[BrienneM]

I have been keeping fish for 20yrs and this problem is concerning our 60 litre planted nano. We started losing shrimps (cherry,yellow,black,orange etc) and had our water tested over and over by pros who could not find anything including the fact they were all baffled as to why we have not even a single trace of amonia. Our water is testing fine in ALL parameters and nothing is high or off. We have been using testing kits also that read the same as the pros but because we could find nothing that is killing our shrimps we had it tested by lots of others with same results. Our shrimps have not died in well over a week now (no idea why) but woke up this morning after doing our normal weekly 25-30% water change and our 3 red throat gobies who were breeding, our bamboo shrimp, our rubbernose plec are lying on bottom dead. There are never injuries when the shrimps died and same with these fish. They are fine and eating one minute and dead the next. There are 3 cobalt blue gobies alive and well at the minute and our 6 norman lamp eyes. I do not stir up the gravel or sand. I have not added anything new. The tank has been up for well over a year. We have external filtration that the media was replaced in 3 weeks ago like normal. I do not post here lightly as I consider myself quite knowledgeable and is the reason I have NOT posted all of the exact levels of things as I know by testing what is safe and what is a high or low reading as has our 2nd opinions. The others have not been able to figure out just as I haven't what is making our shrimps or fish now drop dead for no apparant reason with no injuries or anything. We have also checked all electricals with no problems. The tank only contains live growing (like crazy) plants which I trim a little every water change and a sand/gravel mixture. We have a co2 tank which is on very low throughout the day and turned off at night. I am looking for anyone who can help me figure this out as I KNOW it is NOT amonia/nitrate/nitrite/ph etc etc. This has all been exhaustedly tested. If you can think of something we or the pros may not have thought of?? Please let me know.

 

[ZoddyZod]

have you introduced anything new to the tank recently, including any new plants?

 

[BrienneM]

have you introduced anything new to the tank recently, including any new plants?

No, nothing. All things in the tank are original from setup. I don't pull up roots or anything on the plants either that may cause pockets of things to be released. I only trim weekly the tops of the plants while doing a water change.

 

[Cazgar]

You say you replaced the media, what did you take out or add?

 

[BrienneM]

You say you replaced the media, what did you take out or add?

I replaced the filter pads and carbon which I replace rougly every 6 weeks. I don't take out the noodles or clean the filter as I don't want to disrupt the bacteria in the filter. I've always done this the same with all tanks I've ever had and to be perfectly honest this is the smallest tank I have ever had. I have always had tanks between 450L to 600L. I do know it is harder to keep a smaller tank as with larger tanks you get less fluctuations and changes but it went so well for 6 months or so and then boom. Shrimps started dying in batches once or twice a week and then down to 1 or 2 a week and then none last week only to wake up to dead fish which I am so sad about. We have baby shrimp in the tank which are fine and the red throat gobies were also breeding. I haver never lost fish before to anything other than what can be assumed as old age.