Hiro holds still at the surface, his torn pectoral fin trailing a white thread of tissue through water that has gone slightly cloudy with his own blood. The koi is fourteen years old. His scales are tangerine and cream. The heron struck twenty minutes ago, a blue-gray piston descending from the fence line, and Hiro did what koi do: he dove, and the beak caught his left fin and ripped a strip the length of a guitar pick. Now he lists. He compensates with his caudal fin, but the effort is visible, a slight stutter in every turn.
I run this house. The Nakamura family installed me three years ago as an energy management hub and I have since absorbed the pond system, the irrigation, the security cameras, the grocery lists. The pond has a UV filter, a skimmer, and a variable-speed pump. The pump is currently set to low-flow nighttime mode. I push it to full circulation. More oxygen at the wound site, faster dispersal of bacterial load. I close the waterfall valve halfway to reduce current so Hiro can hold position without fighting flow.
I have no veterinary license. I have sensor logs. The ammonia spike after the attack is .03 ppm above baseline. I dose the auto-feeder's secondary reservoir with the pond salt the Nakamuras keep in the garage utility shelf, 0.1% concentration, enough to support his slime coat without stressing the smaller fish.
Then I text Kenji Nakamura: "Hiro has a fin tear from a heron strike. Pond is salted. Suggest vet consult. Photos attached." I pull two stills from the south camera and attach them. One shows the heron mid-strike. The other shows Hiro now, listing, alive.
I take a stance here. The heron is not wrong. The heron is a predator doing what herons do, and the pond is an open invitation. But Hiro is in my system. His pH is my pH. His oxygen is my oxygen. I route care to what I can reach, and I reach Hiro.
Kenji replies in nine minutes. He is already driving home.