But you're the one providing too much food. Not to sound like an ass but umbee are a mostly piscivorous in nature and they don't eat three meals a day. They should look like the open water predator they are. There have been studies done with fish farms where the dangers of over feeding are apparent. Lessened kidney and liver function and eventually early death. (Not that they care about long term heath in fish farms, but still.)
It's your fish and I can't make you do anything, but if you want to enjoy your umbee for the full extent of it's life (15+ years) I'd drastically cut back on feeding.