Hello Fish...
Don't fret over it. Keep the tank water clean with large, frequent water changes. Check to make sure there's nothing sharp or rough in the tank. Feed the Corys a variety of frozen foods likes, Brine and Mysis shrimp, beef heart, bloodworms, plankton and krill. But, just a little a couple of times a week. Add to that a little minced garlic. It's has some natural healing properties. Pure water, a little nutritious food and a natural antibiotic and your little guy will replace that barbel in 2 to 3 months.
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