Dying Fish At A Rapid Rate!

[Moochela]

I recently moved my fish into a bigger aquarium, a Rio 180, about 145 litre tank, put it a Fluval filter and a heater and let it cycle for a couple of weeks, added a few plants and moved the fish in over a couple of days. A week later I added a few new fish and now they have started dying! Since Sunday, I have lost 6 fish! I have had the water tested twice, the only thing is the nitrates are a little higher so I have put in Stress Zyme as recommended by a fish shop. Now some fish have fin rot and fungal cotton like patches. I treated this wil Anti Fungus and Fin Rot medicine. Not sure what to do, should I do a partial water change? Any help would be greatly appreciated, preferably without a lot of technical terms as I am new to this! There are about 20 fish in the tank now. Stephanie

 

[Harlequins]

Was it a new filter? ,filters don't cycle in a few weeks,what are your water readings like?

 

[Moochela]

Was it a new filter? ,filters don't cycle in a few weeks,what are your water readings like?

Yes it was a brand new filter. Water readings are
CH 8
PH 8
TH 10
NH4 0.5
NO2 1
NO3 40

I had the water tested again and was told that onlythe nitrates were a little high now and that all else was normal.

 

[onebto]

One thing definitely get a decent water change in as soon as I would do a big one at least 50% my humble opinion

Your stats say you have an ammonia reading that is bad as well as some Nitrite and a high Nitrate it would help your tank alot

 

[tropicalman]

If you are still losing fish it may be do to a fish tank starting bloom. what i mean is that if you start up a new tank it may becoming cloudy or have very high spikes it ph measurements and stuff like that. It has happened to me alot, i have eight tanks.