Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
I would rather put the Betta in the tank, not let him sit in a jar.
The jar will build up toxinsm and has no way of dealing with them. The tank will build up toxins, but with some plants and water circulation there is at least some hope that some of the toxins can be handled better. If you need to do a water change on the jar, or on the tank (and you will) it does not matter which you do, it is such a small volume either way it is really easy to do.
Water parameters (note spelling: 'perimeter' is edges of a field, parameter is the correct word here)
Test the tap water. If the NO3 is low, then I would do 90% or whatever you can handle water change to drop the nitrates in the tank. (use dechlorinator if the tap is treated with chlorine or chloramine) Then add the Betta.
If you can get the smallest bottle of nitrifying bacteria that would help a lot. Look for Nitrospira on the label.
Dr. Tim's One and Only, Tetra Safe Start and some others. These will add the right species of bacteria to the new tank so there is only a brief, small rise in ammonia or nitrites.
Yes, get testing supplies for ammonia.