Why tetras are so easy to overfeed
A tetra's stomach is roughly the size of its eye, and a school of twenty can look desperately hungry while needing, between them, less food than covers a thumbnail. Flakes and granules also expand as they soak, so a pinch that looks modest dry becomes a feast in the water — and whatever the school misses drifts down, clouds the water and rots in the substrate. New keepers feed the begging, not the fish: tetras learn within days that a face at the glass means food, and they will mob the surface for a fourth meal as eagerly as for the first.
A portion you can measure with your fingers
For a school of around a dozen small tetras, start with a pinch of fine crumbled flake or micro-granules no bigger than a pea — genuinely a two-finger pinch, crushed between finger and thumb as you sprinkle so pieces are small enough for tetra mouths. Everything should vanish within about two minutes; if food is still drifting down at three, the next portion shrinks. Feed that small amount twice a day rather than one bigger helping, and watch bellies rather than the clock: a gentle rounding after feeding is right, while bulging sides mean the pinch grows smaller, and pinched, flat bellies mean it grows slightly. Weigh nothing, buy nothing — your fingers and the two-minute rule are the whole measuring kit.
Technique that keeps the water clean
Sprinkle the food across the surface in a line rather than one spot, so the whole school eats at once instead of the boldest fish filling up while shy ones go without. Turn the filter outflow down or off for the few feeding minutes if the current blows fine food straight into the plants and corners where it rots — and build switching it back on into the same routine, every time. Sweep a fine net through the water after any feed that went wrong and lift out what sank; a two-minute rescue prevents days of cloudy water. One fast day a week suits adult tetras and trims any creeping excess. If your tetras hang mid-water and ignore the surface, switch part of the ration to slow-sinking micro-granules, which drift down through the school's own level — the same pea-sized total, just delivered where the fish actually feed.
Adjusting as the school changes
Recheck the portion whenever the tank changes: new arrivals, growing juveniles and breeding activity all shift what the school needs, while a tank that loses fish needs its pinch cut at once. Bottom dwellers sharing the tank do not live on tetra leftovers — they need their own sinking food after lights-out, and the tetra portion should still be sized for the tetras alone. If algae starts creeping or the filter clogs faster than it used to, treat those as portion warnings and trim before testing anything else. KinsLe's Care Teams can record the pea-sized pinch and the twice-a-day timing as the school's standing feeding duty, so anyone covering a holiday feeds tetras the same measured way.