There's no greater risk than dealing with live animals. Before getting into it, calculate your costs down to the ridiculous.After figuring your start up: tanks, filtration, back up systems, foods, meds, biz/tax licenses, utilities,insulating, shipping materials (including O2 tank exchanges), shipping accounts (ground and air), waste disposal, insurance, inventory control, vet fees, advertising, tax tools, security services (usually required by biz insurance), etc. You'll need to know, and control, your regular operating expenses like foods, tank maintenance materials, disease control, daily order research (shipping quotes, bulk pricing, etc.), purging, packing, and package pick up or air cargo delivery, daily email and website screening/followup, etc.
Once you've finished calculating your annual expenses, ...DOUBLE IT. It may sound nuts but, it's a necessity to account for those unexpected expenses such as:
Shipment losses (DOAs and mis-routed shipments)
Customer loss complaints (whether real or being scammed these will take a lot of your time and $ to weather)
Disease/vet/med cost additions (example: I had a bout of septecemia run through my systems. Even though I recognized and treated immediately, I still lost $4K of livestock in one week. Plus the loss of potential business when customers looked elsewhere to get their needs/wants fulfilled).
Website maintenance/security/upgrades
Pest Control/Mold control
And a host of other expenses both nickel-and-dime and major expenses that WILL creep up and bite your business in the butt at one time or another.
There are a few like me that stayed the course from either the pleasures of this hobby or self-abuse. But, there are hundreds for every one still in the biz that folded from poor-planning, dis-illusionment, or desperation.
Be honest with yourself when calculating real expenses, business plans, objectives, and projected returns before diving in to reduce any losses and disappointments that will, inevitably, crop up in any business venture.