I would take back the clown loach, not get more. These fish get to be over a foot and need a school of 6. You have to have a HUGE tank to keep this kind of loach. I don't even recall the minimum - I want to say 125g. I know they are unsuitable for my 90g! Your pet store steered you very wrong.
Rasboras and tetras are also schooling fish and need at least 6.
Take back the loach and finish your rasbora and tetra schools, IMO
. Then you can add some cories or kuhli loaches for your bottom.