ADHD forgets to feed the fish
and when she finally remembers,
it is dead at the bottom of the tank.

Well, I suppose dead is an understatement:

a mossy film embalms the body
(at least what is left of it)
its suction-cup maw putrefied
as it suckles the sickle of death.

Half of the body is there.

Half of it has disintegrated.

Imagine existing nowhere and everywhere
all at once; microscopic remnants
defile every particle of water long after
the rest of you has vanished.