Hi i have a 45 gallon hexagon tank with a 10 inch oscar and im going to give my dad a 5 inch pleco and what would be the best synodontis for that tank.

I wouldn't advise putting any other fish in your tank as it isn't really big enough for one Oscar. If you don't have a tank that was big enough to have some tankmates then there are various side syndontis catfish that don't get very big. I'm not an expert on catfish they would have to find a website dedicated to the catfish species. My 2 catfish only reach about five or 6 inches so make perfect tankmates for Oscars. You have to be careful with catfish, many of them reach very large size is indeed. That night he