Not sure what you mean about fish botting.

If you are running a bot, for play while you are not there, your accounts will be banned in short order.
Not really worth an investment into a boxing software option, or even just buying multiple accounts.

If English is not your first language, or if you misconstrue boxing several games is synonymous with botting, then we might be able to help.

With multiple game clients, you have the option of hardware or software broadcasting.
I have no experience with hardware boxing, but there are stickies on the site to cover that.

Something like Mojo (free) will probably be able to send the same key to each client.
Or go with HotKeyNet, which Mojo is based on. HKN is a finished product now (also free).

Keyclone is great for simple key broadcasting (1:1, as in press A, everything else receives A) - it costs $20 per license, and you need one license per computer, but the license lasts forever.

IS Boxer is $36/year, and will run on up to 5 computers at once.
It is overkill for what you want.
Key replication and mouse broadcasting, auto follow.
Master/Active window can jump; slaves/followers can jump independently.

Jamba (a free addon) will cover using items on all clients at once.
Or taking the same flights etc.