USB interfaced micros

Hello all,
I'm just a beginner, newbie in this micro-world :)
Since I'm fond of aquariology and in particular I love to breed and reproduce crustacea (mainly shrimps and crayfishes), I'd like to get something-like-a-microscope to use in conjunction with a pc to get some pictures. Considering that:
- 90% of the use of this microscope will be related to crustacea larvae (e.g., i'd like to observe zoeae stages in the development);
- I don't need an impressive magnifier to do this.
Would you consider buying an usb microscope? Do you have some models or requirements to suggest me for my task?
Thanks a lot :)
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