I want you to act as a financial analyst and provide advice to her. Should she go ahead with the business, since she said it is serving as a side hustle or should she not even venture into it considering that she has no experience and even though she may be able to pay off the debt from her main job, her lack of experience may cause the business to fail ?
The business will collapse within a few months or years. Agriculture businesses need a lot of experience because you are dealing with living things. Any mistake can lead to the death of the fish which will lead to fatal loss. Maybe she wants to learn on the job but the cost is usually high. She has to employ the services of an experienced farm manager to monitor the fish or the business will close down.
Fish farming is highly risky so using a loan to finance the project might have negative consequences if something goes wrong. The worst part of it is that she lacks knowledge about farm management and the fish business. So she will just be experimenting with a loan.
Unless she employs a reliable farm manager the farm will not be productive. Fish farming needs a lot of attention, especially at the tender stage. The farm needs constant monitoring so fish farming might not be a right side hustle.
If she feels she can afford to pay the loan with her income, then it could be a platform for her to learn about the business. But I guess that the business will not be successful from what OP has explained.