can I get a loan on the basis of Fiverr income?
Not from Fiverr.
I’m not sure where you are from, but in the United States, Fiverr income is reported as self-employment income. Assuming you mean going to a bank and asking for a loan by presenting proof of income, you can get a loan as a self-employed individual.
I hope not.
Imagine if your account gets banned for whatever reason. Then what?
You can present yourself as a freelancer and maybe you can get a small loan. Although I wouldn’t recommend it.