Well they say 12" for a full grown one. I have a two year old at 6-8" and he is fat as fat con be. Silvers dont get as big as the rest of the dat family but they are true preditory(sp) fish, you cant trust them realy but out of all the dats they have the smallest mouth imo. I wouldnt trust them with anything much smaller then them. I once saw one of my tigers swipe at papas tail and take of the lyre. By god he was nearly in the toilet.