I didn't think you were overly pessimistic jimo, I appreciate all the help I get here.

I don't have a pool in the tank, so drowning is not an issue, and there is a fair amount of hiding places in the tank out of view if one another.

I will just keep an eye on them, they have lived together since they were tads, so fingers crossed they won't fight.

Thanks for all the advice!

Edit: I have tried playing some tinc calling, but it didn't stimulate any calling of their own unfortunately