Seafood stall supervisor - the live-stock holding daily SOP: water changes, density, the no-feeding rule, and thermal zoning - structure locked, numbers left blank

Write an archivable "Live-Stock Holding Daily SOP" for a seafood
stall - clerks work it, the supervisor checks it. Covers freshwater
fish, saltwater fish, shrimp, crab, and shellfish.

1. Daily rhythm table (the core; tick-box, one column per tank)
- Before opening: walk every tank - aerator output (surface
  bubbling), water color (clear or slightly cloudy is fine; milky
  or foul is not), count of surface-gaspers, dead stock netted
  out and logged. All boxes ticked before the shutters go up
- Midday: water changes (each tank on its "change one-Nth per
  pass" cadence - specific numbers left blank for the supervisor
  to set against this store's filtration), dead-stock sweeps at
  intervals of no more than [N] hours, ice-bed topping (detailed
  in the separate display SOP - one link line here)
- After close: no feeding, ever (own section below), aerator
  check and log, dying stock handed to the markdown-decision
  process (not duplicated here)

The no-feeding section (standalone, must carry its reason):
- Live stock in holding tanks is never fed. Feeding is the most
  common well-intentioned disaster of retail holding: leftover
  feed and waste degrade the water directly, and empty fish
  actually survive longer
- Write it as "reason + rule," never rule alone - rules get
  overruled by kindness; reasons don't

2. Zoning and density
- Zoning decision rules (rules fixed, combinations blank): species
  with far-apart temperature needs never share a tank; species
  that prey on each other never share; heavy oxygen demanders
  (e.g. shrimp at high density) get their own tank. Which of this
  store's species sits where - the supervisor fills one zoning
  table by these rules
- Density ceilings: every number left blank for the supervisor,
  but the feedback rule is fixed - a tank with persistently
  elevated mortality gets its density cut first, other causes
  second. The final judge of over-density is the mortality rate,
  never any reference table

3. Exception links (don't duplicate, just point)
- Accelerating deaths -> triggers the Live-Stock Mortality Tiered
  Alert process
- Power failure -> backup power to aerators -> partial water
  changes to cut density -> transfer to large containers with
  manual aeration (in that order)

4. Checks and ownership
- Every action carries: who / when / how verified (tick sheet,
  photo, logbook)
- The supervisor spot-checks daily - method stated: not by reading
  the tick sheet (sheet-copying is the destiny of every tick
  system), but by picking one tank at random and asking the clerk
  on the spot: "this tank - water changed today? what time?" Only
  ticks that survive being asked about are real

Format: two A4 pages maximum, tables first; every value tied to
species or equipment left as a [blank] for each store to fill -
an SOP that hard-codes someone else's numbers is an SOP that
was never written.

Why it is written this way

Holding is the seafood stall's one capability with no equivalent in neighboring trades: a vegetable clerk's craft is preservation; a seafood clerk's craft is keeping live animals alive at retail density - farm work compressed into a dozen square meters. That is why the SOP's skeleton is a daily rhythm table rather than a list of precautions: holding quality comes from running the rhythm, not from running inspections.

The no-feeding rule gets its own section and must carry its reason - the single most important design choice in the document. The kindest mistake a new hire makes is feeding: the fish have looked hungry for three days, one handful of feed goes in, the water collapses that night, and the tank dies in a sheet by morning. Four characters of "do not feed" cannot stop kindness; "feed and waste degrade the water, empty fish live longer" can. Rules get overruled by kindness; reasons don't.

Leaving every number blank runs deliberately against most templates: tanks, filtration, and aeration differ so much between stalls that a "kilograms per cubic meter" copied from the internet is farm data - applied to retail holding tanks it becomes systematic mortality, and it arrives wearing the confidence of a standard, which makes it more dangerous than no standard at all. The SOP fixes only two things: structure (rhythm, zoning rules, feedback loops) and blank cells; whether density has crossed the line is decided by the mortality rate - the most honest sensor available.

The supervisor's check is written as "pick a tank at random and ask on the spot" because every tick system's destiny is to be defeated by copied ticks; the only defense is keeping every tick alive under the pressure of "I might be asked about this one." A checking regime is never designed for the sheet - it is designed for the sheet inside the person's head.

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