Brief the sitter on pace, not just tasks
Most sitter instructions list tasks — feed this, top up that — and for a young tank that's enough. A tank of old fish needs the sitter to understand the pace: everything here is slower, the fish rest a lot, and the job is as much watching as doing. Say this out loud before you leave, because a sitter who expects lively fish may try to fix a quiet tank by overfeeding it, or panic at normal old-fish stillness. Equally, they need to know that in this tank a small change is a big signal — the fish have no reserves, so early news is the whole point of having a human there.
Feeding: measured amounts and the watch afterwards
Leave food pre-measured for every day, labelled, so 'a pinch' never becomes a feast — old stomachs and old filters both cope badly with generosity, and uneaten food in a senior tank is a water-quality problem within hours. Then ask the sitter to stay for a few minutes after each feeding and simply watch everyone eat. That watch is the real work: the fish who always comes and didn't, the one who mouths food and lets it fall, the one being shouldered aside. Those observations, sent to you the same day, are worth more than any gadget reading. Show the sitter what a normal feeding looks like before you go, ideally in person at the tank.
What normal looks like in an old tank
Describe each fish's ordinary old age in plain terms: who naps on which leaf, who is slow to start in the morning, who has looked tatty but stable for months. A sitter who knows the individuals won't waste worry on the wrong things or, worse, dismiss a real change as 'just his age' because nobody told them his age looks different from this. Point out the fish you watch most closely yourself, and be honest about any you privately think is fading — the sitter should know where your own concern already lives.
What should trigger a phone call
Give a short, unambiguous list. Call you the same day if a fish misses two feedings running; if anyone is gasping at the surface or resting in the filter flow; if a fish is hiding all day who doesn't usually; or if you find a fish dead — and send a photo of the tank with the message. Also make clear what not to do: no extra food to tempt a fish who is off it, no remedies tipped in, no big water change unless you have agreed it in advance. A sitter who knows the boundaries of the job does it calmly; one left guessing improvises.
Leaving it all in writing
However good the conversation, put the routine, the amounts, the normal-for-each-fish notes and the call list in writing where the sitter can reach them without phoning you first. Keep it to a page or two they will actually read, in the order their day with the tank runs. Then go away and let them do it — the written word plus a calm handover is what turns a favour into reliable care.
All of that briefing belongs in one place the sitter can open at the tank, and KinsLe's Care Pass hands them temporary, clear access to the routine, the watch-fors and the key details for exactly the days you're away.