Software dev here. As mentioned Wix, Squarespace or Shopify are going to be your best bets. I haven't used Wix or Squarespace, but I have some experience with Shopify so I would recommend looking into them. I think they are a bit more expensive than the other two, but the customization, plugins to help automate things and support is quite good and extensive.
Before going down this route, I would really look into the cost and see if you are going to be selling enough coral to make it worth your time. Unless this is a side project for fun. If that's the case go big and have fun!
Think about:
How long it will take to setup and run. Packaging, shipping, troubleshooting customer issues with the site, keeping it up to date
Purchasing the domain(usually quite cheap, but still an expense)
Transaction fee's from stripe
A local reefer was starting his own frag shop. Had a couple 400g tanks filled with imported frags. He was using something like Wix for his site. He said the biggest headache and time sink for him was keeping the site updated and running. Between taking pictures and adding them to the site, dealing with customer questions issues, general site upkeep. He said it was the most time consuming part of the operation.
When selling things online you're taking peoples credit card info and dealing with money. This leaves much less room for error.
Good luck!
www.squarespace.com
