i have a 125ltr fluval roma. the tank is new but the water and filter and plants sand fish etc are mature. my old tank leaked so i bought a new one the fluval roma the fluval is the same size as the old jewel after transferring everything back in to the new tank it all looked good but its been 20 days and i have lost 4 fish over the past 2 nights 3 mollys and 1 dwarf gouramii couldnt see any obvious reason they were acting very lethargic and just drifted round the tank. i moved them into a plastic breeder trap to stop the other fish pecking at them. i did a water test and the results were as follows ammonia oppm nitrite oppm nitrate 2.5ppm ph 7.6
the only thing that came back as odd was the ph which is normally 8 ( i live in a hard water area)
my balloon molly is doing the same thing and looks in bad shape i dont know what to do
the tank is well planted and i have done a 25% water change yesterday
i moved the fish into a seperate vat with heater filter aqua stone plants all in together with the fish the filter was still running. i used aqua safe on the new water but most of the water was from the vat with the fish
5 red tuxedo platys 2 adult black mollys 2 baby black mollys free in tank 6 months old 4 head and tail lights 1 hillstream loach 1 Siamese flying fox 1 blue dwarf gourami the balloon molly has just died
the test kit is a API freshwater master test kit
the ph test on tap water came back as 8.2 and the nitrate test on tap water came back as 0ppm
It sounds like something has stalled your cycle. With the amount of stock you have, you should see more nitrate than 2.5ppm in the water if the tank was cycling. What filter are you running?
How long had the tank been running previously? What was your typical nitrate level in the tank prior to a water change?
The other things to consider are whether anything at all was added to the new tank that wasn't in the old one: new decor or gravel, new plants, extra fish etc., and how clean the new tank was. Was it new or used? Did you clean it before use and how?
EDIT: Also check the water temperature in case there's a problem with the heater
The nitrate level does seem to be very low compared to the level you usually see so I think your cycle has either stalled completely or slowed down for a while after the move. That may have resulted in a temporary spike in ammonia and/or nitrite which would account for the fish being unwell and dying. I can only assume that as this is the original Juwel internal it will have taken some time to remove it from the old tank due to the silicone holding it in place. The time that took while it was switched off and out of water will have caused some filter bacteria to die off.
I take it it's not siliconed into the new tank, but just sitting loose? If it is siliconed, then I take it the filter must have been off for a couple of days for the new silicone to dry? That would kill most if not all of the bacteria.
As you currently have no ammonia or nitrite showing, and nitrate is appearing you may be over the worst of it. Test daily for a while and if any ammonia or nitrite appear, do a partial water change to reduce the amount in the water. This guide to dealing with ammonia and nitrite spikes will help with this.
Can I just check whether you used any silicone when fitting the filter into the new tank?
Some of the other fish may still be suffering after effects so keep an eye on them, but the main thing is to monitor ammonia/nitrite daily and change water when needed for a while until you're sure everything is back to normal.
we did not use silicone my dad drilled a hole into the outer plastic ( it doesnt affect the sponges or pump) and then pushed a sucker that sticks to the tank through the hole. we wanted to avoid using silicone