I have a 75 gallon freshwater tank that has been running for the past 6 years. In the last year, I only recall one loss; in the last 24 hrs, I’ve lost 10 neon tetras.
Stocking:
30 neon tetras
10 skirt tetras (glow, black, white)
6 Congo tetras
6 Phantom tetras
5 Ottos
A dozen bristle nose pleco fry
3 amano shrimp
Planted, not running CO2, fluval FX4 filtration, dual heaters.
Recent tank activity:
On Saturday, I rehomed 9 adult bristle nose plecos as they kept breeding and it was hard keeping the substrate looking nice between water changes. I picked up 6 ottos to replace them.
Sunday I did a 25% water change and decided to replace 3 of the 4 fx filter pads, I did not disrupt the bio media.
Monday I lost one Otto but don’t think anything of it.
Today I lost 10 neons and counting.
I also see a large bloom of clear algae, I assume this is an increase in visible biofilms due to removing plecos.
Current Parameters and Actions taken:
Temp: 77.9
Ammonia: between 0 and 0.25 (slight collar difference on api liquid test)
Nitrite: 0
Nitrate:0
I performed a 50% water change, dosed Prime, added Fritz turbo start, added a bag of purigen and bag of activated carbon to display tank (temporary), added 4 air stones.
Pretty sure changing the filter pads was my mistake… open to any other ideas, also open to any additional steps I should take now and over the upcoming days.
I plan to test water again in the morning, possibly dose prime again, do additional water changes if ammonia is still showing.
Pretty bummed today.
Posted by DamageUnhappy2020
4 Comments
Add stability to the regiment as well. Keep doing water changes. Filter might be catching up again with new stock added. Sort of new tank syndrome? Just a guess
Hopefully settles now. Perhaps a nitrite poisoning. Nothing to do with they just pull through or not
This is why I always have at least 2 filters.
It’s a mature 75 gallon tank with a lot of surface area, you’re overfiltering with a nice fx4 that has a ton of surface area, you just removed the 9 biggest fish that created the most waste by far and replaced them with 6 small fish that don’t create much waste, you did a large water change right before the issues started, you’ve tested the water and it’s reading 0 nitrate and nitrite and almost no ammonia even though 10 fish died in it today and you had no issues until right before you added the ottos.
I don’t understand the focus on replacing the sponge filters as a cause. Seems pretty obvious the ottos had some kind of health issue when you bought them and this is the problem. Maybe some sort of bacteria and this is why the smallest fish with the worst immune systems are the ones dying. I think you should get them out right away and treat them and the main tank with paraguard or something similar and see how the ottos are doing in a few weeks.
It’s far more likely the oto’s added something that’s killing the tetras. Did you quarantine them?
Even if you removed the filter it’s unlikely fish would die so soon.