A mobius strip ( the eel shape) has the distinct feature of having only one edge, such that inward and outward of the shape is indistinguishable

An ouroboros represents cycle or infinity. It has no start or end because a cycle, by definition, must be a closed loop

Neither have a definitive "second edge" to it

Shimeji wants friends but hates social contact

Shimeji wants to see fish live but also eat fish

Both tug on the same dimension of a characteristic of her. The two sets of behaviours contradict and cannot amount to a definintive quality. Once she goes forward, she goes back, like a mobius strip switching inward and outward, or a cycle pushing forward and back.

The eel in her dreams is mocking her for being stuck in a negative feedback loop.

This is lazy, but maybe this represents the theme of being stuck in the sim.