Brine is like junk food, feed it something more nutritional like krill ir mysis, any marine based seafood will do. You can buy a couple raw shrimp at your local seafood counter, just keep the pieces small, it will have a easier time especially since it's bleached. Selcon and zoe are aquarium food boosters, they add fatty acids, lipids and vitamins. Feed fresh frozen seafood, as it defrosts, give it a couple drops of the booster. I'd forgo the flake food.
Overfeeding, you can but it will only eat as much as it want to eat. Extra food will be let go of and dropped and will add extra nutrients in your system. Remember it must eat and expell through the same opening so watch for this, deflating and expelling. I would feed a couple times a week when fully inflated.