Well basically, I walk up to the tank.
Just kidding. But really, if I do so much as get up from my sofa or walk even remotely close to the tank, there they are. "Is it time? Can we have a bite?" Some days they get Omega One, some days spiralina, some days pellets. Some days peas, they really like veggies so I enjoy feeding them stuff from the fridge. Just whatever I feel like! Its tempting to overfeed when they crowd like that, I occasionally give in.
It gets kind of annoying how they crowd sometimes, because I want to see them do what they do. Dig, chase, whatever. But, I can't even glance at them without a crowd at the front of the tank watching my every move.