You should get some sinking shrimp pellets and maybe some algae wafers. You can also feed veggies. You really shouldnt let any food sink to the bottom when you feed.
What kind did you get?
IMHO you can skip the Algae Wafers, Cories are meat eaters. They may nibble on a veggie wafer,but they eat meat. Shrimp Pellets, Catfish pellets, Frozen Bloodworms, live Blackworms, Frozen or Live Brine Shrimp are all good.
I feed a variety.
Shouldn't let food sink to the bottom ??? Huh ?
When I feed flake, I do feed a bit extra so some makes it to the bottom for my Cories. I have fast fish, so I make sure my Cats get food.
Planet Catfish is an awesome site for good Cory info.
Congrats on the trilineatus
I have C. habrosus and will also have C. hastatus
Make sure you do PWCs and keep the substrate clean. Poor water quality and dirty substrate appears to be the leading cause for infections and loss of barbels in Catfish.
Mine pose on my plant's leaves as they are small enough to do that
Here is a iphone vid of my tank during a feeding frenzy
They are eating Frozen Baby Brine Shrimp (my Threadfins have tiny mouths)
Feeding time 10g Shrimp Jungle - YouTube