Favorite single specimen tank species?

[IHateDisney]

Of course there's stuff like Flowerhorns, Bettas, Oscars.
Crystal-eyed catfish are one of the few I have heard that are so aggressive that they must be kept alone and can even attack their owners maintaining the tank, but I have heard so little about them in general other than their hyper aggression. E-cats too are catfish that should be kept alone.
Needle-nose gars are similar to that as well.
Mature triggers for marine.
What comes to mind for you?

 

[tlindsey]

Of course there's stuff like Flowerhorns, Bettas, Oscars.
Crystal-eyed catfish are one of the few I have heard that are so aggressive that they must be kept alone and can even attack their owners maintaining the tank, but I have heard so little about them in general other than their hyper aggression. E-cats too are catfish that should be kept alone.
Needle-nose gars are similar to that as well.
Mature triggers for marine.
What comes to mind for you?

Welcome aboard
Aimara Wolfish
Black Piranha

 

[SHAWNS2]

As i look back on it, seems crazy that this was one of my first fish ive kept, and still have over the years, my good ol' Greenspotted Puffer, Ruffus haha

 

[twentyleagues]

Most puffers in general.

 

[Kolton13]

Some people keep them in groups. But my gulper catfish

 

[DMD123]

My favorite are my personal tanks with individual puffers in them. Both my lurkers have their own 65B.

My Arrowhead puffer... Before and after, lol



My Hairy puffer

 

[Ruturaj]

I keep flowerhorn for aggressiveness and color. Few people think cichlids are smart enough to recognize owners and have personality, I am not sure how much of that is true.

For next tank I would mostly get a red dovii.

 

[Joshuakahan]

Of course there's stuff like Flowerhorns, Bettas, Oscars.
Crystal-eyed catfish are one of the few I have heard that are so aggressive that they must be kept alone and can even attack their owners maintaining the tank, but I have heard so little about them in general other than their hyper aggression. E-cats too are catfish that should be kept alone.
Needle-nose gars are similar to that as well.
Mature triggers for marine.
What comes to mind for you?

Fahakas are cool solo fish
Heres one I had

 

[celebrist]

If I had to dedicate my 450 to a single fish I would have an aba aba knife

 

[DMD123]

My other solo fish, my trimac