Need Help With Small Salt Water Fish Method

You can half cast most small panfish and skin mount them. It's a simple process. I've done both freshwater and saltwater fish using this method.

 

Those were possibly eviscerated and freeze dried. On commercial fish, there will always be a "pretty side", unless it's a Masters Level competition fish. Your other option is reproductions.

 

On the small fish you are using, you do not need to worry about removing any internal organs especially on thin flat fish like your Moorish Idol. Should you choose to plump the fish up, just use some laytex caulking. You also should not have much of an issue with scales as many reef fish are void of scales, like Clownfish. Freeze drying, along with the half cast method as Joey mentioned and wax molding will all work. A cheap and easy way is to freeze the fish in your position choice, then make multiple dips in clear Flex Wax. Once you have built up a wax shell, cut open the back and remove the fish. You can then pour or inject the wax shell with a variety of different materials like two part plastics. Then, when your casting material cures you remove the wax shell by hand or run it under very hot water. Flex wax is a very low temperature material and will melt away under hot water. The only downfall with this method is you can only get one cast. Hope this helps