Well, she's not dead yet!  Robert noticed that, Trippie, one of our triplets--three red-colored goldfishes-- was acting sluggishly in the outside pond. This is how two of our other fishes began to act before they died from unknown causes. 

Robert gently caught her in a saucepan and transferred her to Goldie's vase tank inside (next to the TV--which we think they watch.)  Now she's in hospital, hopefully recuperating.  She looks rather bloated, so we are thinking that she got overfed last week (goldfish apparently tend to eat and eat without much regulation of their intake.)

Trippie personifies depression.  She literally sinks to the bottom.  She lays her head against a rock and gently breathes her gills in and out.  She stares (although I did see her blink when I was watching her straight on.  I was quite excited to see it.) She moves slowly and sometimes lists to the right side.

She's lasted through the day, so we can only keep an eye on her.

We put a little Epsom salts in the water as a laxative.

Goldie, on the other hand, swims around quite perkily.  She seems to recognize us--expected food-- as we get close to the tank. Robert is careful to feed her only two or three pre-soaked fish pellets (the size of her tiny eyeball) to avoid overfeeding her.  She seems to exhibit no sympathy for her tank-mate's predicament.