Um... SS, the purpose of Bulb Yoshi is not seeing in the dark but being able to see and interact with things you normally can't see or interact with. [/offtopic]
Good news: I have another Bulb Berry which i bring to Ag-e, who feeds it to Bulb Yoshi.
Bad news: The cave is filled with enemies, and if you just lose 1 HP, Bulb Yoshi's powahz are no more.