Lionfish

This apsolutely gorgeous specie would probably be an aquarist dream come true. But one should not forget its highly venomous spiky fins. Beware when handling it with the net. If the fish gets in-tangled do not, never ever, try to free it with hands, but rather be patient and wait till the fish free it self.
The fish in the photo is the Pterois miles (Devil Lionfish).
It grows to 30 cm and can only tolerate it's own specie. A good tank mate for this fish is the Triggerfish. This fish deserves large aquariums to thrive.

Photo by Dusko Bojic.