Dont count on it for aquarium fish. This is done by the use of fibreglass casts of actual fish that the taxidermist purchases and paints. I think you can see where I am going with this, for instance there are hundreds of Largemouth bass 'blanks' available because they (and other gamefish) are very commonly mounted. The less common a fish is the less sizes and positions there are available. Most common game fish have a good selection and you have an excellent chance of there being a blank of similar (note I did not say exact) size available. 99% of the time with aquarium fish you are looking at a good old fashioned skin mount (so bring your fish AND some good pics). The disadvantage of skin mounts is that they will exibit some small amounts of shrinkage in the fins and branchiostegal rays etc. (anywhere fleshy that cannot be skinned) The advantage of a skin mount is that the natural patterns of your fish right down to the small details will still be apparent when the taxidermist 'paints' your fish. Paint is a bad word here because a top notch taxidermist will use many transparent layers of color and even then as sparingly as possible to simply restore the natural color of the fish, not try to completely replace it like an artist would do in an oil painting.
P.S. cost varies all around the country but a replica is almost always more expensive.
