A betta is one of the easier fish to place in a sudden evacuation because he is a single, solitary fish who needs a small volume of warm water — and one of the easier fish to place badly, because that small volume must stay heated, covered, and calm. The realistic options rank by warmth and supervision, not by container size.
First choice: a trusted person's home, with heat arranged
A friend, relative, or neighbour who will actually keep the betta in a lived-in, warm room is the strongest option for most sudden departures. He travels in a lidded cup or a doubled fish bag filled mostly with his own tank water, carried dark and upright, and at the other end he settles into whatever clean, dechlorinated container the host has — provided it is covered, because bettas jump with no warning, and warmed, because a betta in an unheated jar on a cold counter fades quickly. If the host owns fish, he still gets his own container: a male betta cannot be parked in someone else's community tank, however peaceful it looks.
Second choice: staying home, with a checker coming to him
If the absence is short and your home is safe and powered, the betta may be better off exactly where he is, with a trusted person calling in. His heater, filter, and familiar planting stay undisturbed, and a healthy betta tolerates a few days without food more calmly than a journey. What the checker must actually do is narrow: confirm the heater and filter are running, glance at the fish, and feed only a pre-measured portion if the absence stretches — most harm done by home checkers is overfeeding by kind people. This option collapses if the home has lost power or may be unsafe to enter, which is when the travelling options take over.
Third choice: a sitter or shop that genuinely keeps fish
A professional pet sitter who already cares for aquariums, a local aquatic shop that boards fish, or a vet practice with exotic-pet facilities can all work for a betta, and all three vary enormously. Ask the blunt questions before you hand him over: will he be alone in his own heated container, who feeds him and how much, and what happens if he looks unwell. A service whose answers are about dogs and cats rather than water and temperature is not set up for a betta, whatever its general reputation. Take his usual food with him, in a portioned container, so enthusiasm cannot replace his routine.
What travels with the betta wherever he lands
Send the same small packet with every option: his food portioned, water conditioner measured for small volumes, a note giving his feeding amount, his water-change rhythm, and the temperature his tank runs at, plus anything about his temperament or health a stranger would not guess — a betta that hides for a day in a new container is normal, and the host should know not to chase him out of hiding. Photograph him before departure so his fins and colour can be compared on return. Organising that handover through KinsLe Care Pass gives the person sheltering the betta temporary, clear access to exactly those routine details for exactly as long as the emergency lasts.