300 Gallon

[the big kahuna]

Need suggestions for a solo fish for my 300 96x30x24. I'd consider a breeding pair depending on fish. Must be large at least 20 inches, colorful, aggressive and an active swimmer. I'd love to have a large Dovii but haven't seen any adult males for sale. I currently have a 20-22 inch Aimara in there solo but tho he's insane and overly aggressive, most of the time he's just sitting at the bottom unless you approach the tank.

 

[Deadeye]

Have you considered a fahaka or mbu puffer? Maybe not the most colorful, but two of the most aggressive/interactive fish on the market. Mbu get very large too. Fahaka stays much smaller.
Some adult dovii pop up for sale on here ever now and then. Other good cichlids would be umbee or festae.

 

[carterpop421]

Arowanas would be ok

 

[Backfromthedead]

Go salt, simple fowlr setup with a solo clown trigger, tesselata moray, arothron puffer, or maybe a pair of large angels of your choice. Clown trigger checks all the boxes you mentioned, perfect size tank for it imo. Sweet tank size one day I will have one like it.