Cory catfish questions..

[Fishmanic]

Well RainGamma is a gender neutral name.

 

[Fishmanic]

If you did decide to get a 5 gallon tank for your Betta, I would transfer some of the substrate from the 20 gallon into the 5 gallon. Then if you want cories and other fish in your 20 gallon tank, discard the present substrate and get some type of sand for the substrate. Cories really like fine sand as opposed to gravel. You could even have sand substrate in both tanks as it's easier to clean than gravel.

 

[Byron]

I agree on the substrate, definitely. Sand is frankly a must for cories, and it is easy and natural. I use play sand, inexpensive and ideal as it is the most refined sand. Cories love it.

On the GH, KH, pH, you may be able to ascertain these from the website of your municipal water authority (or call them). Make sure you get the number and their unit of measure [same holds for any store tests]. The GH/KH will not change much so once you know what is coming out of the tap, you're set to go.