emergancy set up

I’ve had a tank up and running for 2 months now and I have 2 female bettas, 6 cardinal tetras and 4 cherry shrimp in a 48lt tank. My bettas where the first fish added and I’ve never had any problems with fighting or chasing …. Until I added my shrimp! Water parameters have been fine for 3+ weeks...

I have just noticed white spot in my tank, I have bought the treatment, but I have an elephant nose and need to remove him before i can treat the tank, I hav a spare tank but it is not up and running. how can i best set it up to put the elephant nose in asap so i can treat the other fish in the...