You can boil the fish fillets on a high setting.

你可以设置在高挡位上煮鱼片。

《柯林斯英汉双解大词典》

An even slower boil with no bubble, only the barest movement on the surface of the liquid, is cablled "to shiver, " frémir, and is used for poaching fish or other delicate foods.

还有一种更慢的连气泡都看不到的煮沸方法，只能观察到汤汁表面轻微的波动，这叫做“煨”（frémir），主要用于炮制鱼类或是其他易碎的食物。

youdao

Please boil down the fish soup.

请把鱼汤烧得浓一点。

youdao

Blocking the wind with his torso, Henry strikes the third match and leans forward over the bowl of a hollow pine stump, half hugging the crude hearth in which he intends to boil their string of fish into a chowder.

NPR: Excerpt: 'Woodsburner'