Fishdoc.net - Frequently Asked Questions - ANSWERED
Question: What magnifying power is necessary to perform biopsies on fish?
Related links

Microscopy

Answer:

A magnifying lens will seldom yield a diagnosis of fish diseases, but a microscope of amodest power, for example, 40 x is sufficient for most diagnostic work. For some of the very smallest parasites, a combined power of 400x is required; in the specific case of Costia.

Related items

Hardware for successful fish keeping