Fin Rot and bio boost?

[Tabscat]

Hi, I'm relatively new to fish keeping and need some advice!

We got a new tank and set up for a week before adding any fish
Then added some WCMMs which have been fine for 3 weeks
Last weekend, we added 3 longfin panda Cory's, and had some problems
We think they came with fin rot, and unfortunately lost one yesterday one of the others has a bit of tatty fins, we have been treating for 3 days with Kingbritish fin rot treatment, but also the tank nitrite is a little raised (about 0.5 to 2mg/l)

Normally for the nitrite we would add a bio boost and water change, but after some googling it seems this isnt good for the fin rot treatment??
Any advice would be very appreciated!

 

[tomiyama]

Corycats are very sensitive to ammonia and nitrite which need to read zero. Unfortunately they are suffering from new tank syndrome and the fin rot is a sign of poor water quality.
Your should:
1) Do frequent daily partial water changes using dechlorinator/water conditioner the same temperature as the tank
2) hold the siphon near the bottom of the tank but do not disturb the gravel as the beneficial bacteria are slowly trying to growing on the surface of the aquarium and in your filter
3) feed sparingly every other day as the food and fish waste will contribute to the toxins in your water until your tank is fully cycled (unfortunately it isn’t cycled yet).

Hopefully your two little ones will make it, and is they don’t, preform the fishless cycle before adding anymore fishies....