What key element concerning startled fish behavior limits their escape options when encountering an obstacle?

Answer

Lack of a true reverse gear means their only option may be forward momentum

When startled, fish often react by moving rapidly away from the stimulus, and since they generally lack a true reverse gear, their only immediate option is maintaining forward momentum into whatever is blocking their path.

What key element concerning startled fish behavior limits their escape options when encountering an obstacle?
animalfishattackfatalityneedlefish