flOw doesnt usually explain itself well..at all. sometimes its hard to figure out the abilities each new organism, so heres a guide.

SNAKE - swims faster. very useful for speedruns.

JELLYFISH - spinning. it lures enemies in, and makes your mouth bigger. not exactly useful, but neither is the jellyfish.

MANTA - a dash attack. very fast, very useful.

ELECTRIC EEL - cloak 'n stun. hides you from enemies, and if they touch the electrodes near your head they get stunned. not very helpful for speedruns, since it slows you down.

PREDATOR - homing attack. homes in on health circles, and can be useful in specific situations (i.e. dashing into a red circle to send you downwards)

CREDIT SNAKE - same as the original snake. no difference.