Ichthyophobia (3.5e Flaw)
From D&D Wiki
You are afraid of fish and aquatic beings.
Effect: Any time a character sees or thinks he sees an aquatic creature that is within 15 ft. of them, they must make a Will Save (DC out of 15) or become shaken. For every round the character can see that the creature remains within 15 ft. of the character, he must make another Will save or become shaken again. (or worse, see fear.)
Any time a character is in combat with an aquatic creature, they must make a Will Save (DC of 20) to stay in the battle, otherwise they must take refuge out of harms way at a minimum of 50 ft. However, every round the character must pass another Will Save (DC of 15) to stay in the battle.
Note: If the character does not know the creature is of the aquatic subtype then he does not become afraid.
Benefit: Bonus Feat.