It had several plot lines:
One was a boy who discovered a "baby" sea creature who kept it in his bath tub, for a while.
Another was a female (brunette) marine biologist who also discovered evidence of these creatures.
The third was a man who's brother was eaten by one of the deep sea creatures.
They all "find" each other in the end.

I don't recall any of the actors or I'd just check on IMDb.

This has been bugging me. Thanks!