What size tank? Parameters? How long ago did you move them?
Unless you've seen the tetras harassing the cories, I would guess they are timid because of the new environment. Although serpaes are notorious fin-nippers, I've never really seen them go after bottom-feeders.
The Serpae may harass the corys unless you up the Serpae school to 6 or more. What size tank do you have them in and what type of substrate and decorations? Driftwood? Live plants?
I have a 20 gal tank with 2 fake plants and carribean substrate gravel. And 3 different size hollow rocks.
Is it a 20 long or high? I'de add 3-4 more Serpae and 3-4 more Corys. They will then most likely keep to themselves and harass each other instead of other tank mates. I have a 55 with 5 Serpae a Pearl gouramI 12 Vonrio tetras some guppies some Corys and a couple other various inhabitants and my Serps have never gone after anyone except their own. Not damaging just what appears "pecking order fun" and i've had them over 2 years. But at the same time my tank is heavily planted so there are blind spots and plenty of cover. Couple pics of my 55 and my Vonrio school
Just to give you an update. I decided to remove the serpaes and put them in 5 .5 gallon tank. Bullies need to be by them selves.