Copy paste what is written in the book of tobit concerning fish and healing.
"I did not know there were birds perched on the wall above me, till their warm droppings settled in my eyes, causing cataracts. I went to see some doctors for a cure, but the more they anointed my eyes with various salves, the worse the cataracts became, until I could see no more. For four years I was deprived of eyesight, and all my kinsmen were grieved at my condition."
-Tobit 2:10 (New American Bible)
"Now when the boy went down to wash his feet in the river, a large fish suddenly leaped out of the water and tried to swallow his foot. He shouted in alarm.
But the angel said to him, "Take hold of the fish and don't let it get away!" The boy seized the fish and hauled it up on the shore.
The angel then told him: "Cut the fish open and take out its gall, heart, and liver, and keep them with you; but throw away the entrails. Its gall, heart, and liver make useful medicines."
After the lad had cut the fish open, he put aside the gall, heart, and liver. Then he broiled and ate part of the fish; the rest he salted and kept for the journey.
Afterward they traveled on together till they were near Media. The boy asked the angel this question: "Brother Azariah, what medicinal value is there in the fish's heart, liver, and gall?"
He answered: "As regards the fish's heart and liver, if you burn them so that the smoke surrounds a man or a woman who is afflicted by a demon or evil spirit, the affliction will leave him completely, and no demons will ever return to him again.
And as for the gall, if you rub it on the eyes of a man who has cataracts, blowing into his eyes right on the cataracts, his sight will be restored."
-Tobit 6:3-9 (New American Bible)
“Tobiah went up to him with the fish gall in his hand, and holding him firmly, blew into his eyes. "Courage, father," he said. Next he smeared the medicine on his eyes, and it made them smart. Then, beginning at the corners of Tobit's eyes, Tobiah used both hands to peel off the cataracts.”
-Tobit 12:11-13 (New American Bible)