In my opinion depending on your country's regulations, if your country has legalized cryptocurrency as a payment, then it will not be a problem.
So when your pet shop accepts payments with bitcoin it will be legally safe. For bitcoin exchanges it must have a website itself and also must
get government permission. But I am glad that your pet shop accepts payments with bitcoin, this is a great way to promote bitcoin to be known
by more people.
In any case, if we are talking about illegal business within a certain country, then the use of cryptocurrency should be only according to a specific law, that is, on completely legal grounds. Undoubtedly, every store, including a pet store, can use cryptocurrency as a means of payment, but the report to the tax service on income, the store should be sent accordingly. but exchanging cryptocurrencies is a completely different line of business, as opposed to trading in pet products. And for this you need to have really certain government permissions.
The fact is that in the laws of any country there is an appropriate regulation for the activities of exchange offices for currency. this activity is carried out by banking institutions and non-banking institutions. in order to obtain permission for a non-bank exchange point, you still need to register a non-bank financial company and obtain a General Currency License of the state bank of the country.