John, your weird regardless of your pets lol.
Leopard slugs can reach around 20cm in length, there supposedly found all over australia but originally from europe. I've never managed to find myself any. I wanted to keep them awhile back too. As was stated previously red triangles are native and also reach a considerable size, and here is another fun fact for all, leopard slugs while mating twist around one another constantly until slime builds up into a "rope" which they then hang off of below tree branches too mate, also when there genitals come out they also twist together and end up looking somewhat like a fluro glowing blue flower. Its quite amazing too watch, im sure there would be a video on youtube or something. John if you get some swing me 2, since there all hemaphrodites you dont need specific m/f pairs.
Cheers
Steve