The Number One Bully In Your Aquarium The Red Devil is the undisputed king of freshwater tanks. This massive cichlid, along with the Jack Dempsey, is known for being big and aggressive. Don't be fooled by their names — these fish are brutal with smaller tank mates. I learned the hard way when my Jack Dempsey wiped out my swordtails. Over in saltwater tanks, size doesn’t mean much when you’ve got damselfish and clownfish running the show. Small but scrappy, they’ll fight anything that steps into

The Yellowtail Damselfish is such a beautiful species! We've had our group - which now live in our large, 125 gallon reef tank - for almost 10 years, and they're still as wonderful as the day we got them! Do you keep damselfish in your reef tank? | Fluval