Can anyone recommend a species of lobster that grows large for freshwater? I have a decent sized tank and was considering getting a large lobster as a feature in there.
Lobsters are Marine/Saltwater. Crayfish and Prawn are freshwater, for crayfish I'd suggest getting a Cherax quad. It's docile, can be kept in small groups, easy to care for and easily reach 9-10" as adults.
Yeah, stick to the yabbies and other Aussie crayfish if you're looking for large size. The American Cambarus, Procambarus, and Orconectes mostly max out at 8" or so.