Pond UV's are often just used for algae control (hence they are often called UV "Clarifiers"). Aquarium UV's tend to be for the benefits of parasite control and the like. That requires a much more powerful UV unit than does simple algae control. So, just make sure you are comparing apples to apples. Other than that, there's no reason pond equipment can't be used on an aquarium.
Check the fitting sizes. Ponds often use larger diameters such as 1.5" and up which are uncommon in aquariums. AquaUltraviolet, for example, has 3/4" and 2" versions of their otherwise identical units. Even 3/4" is a bit awkward to use with smaller canister filters which are often 1/2" or 5/8".