[Oscar6]

Tank will hold any of the fish you ask about, and you are correct... not an Oscar. I find that of the 3, the GT will likely be the most personable. Your water is more South American friendly as well. The head lump you dislike is a water filled sac that grows as a sign of dominance. Unlikely to be much to worry about in a single fish tank. EBJD, while always a fan favorite for looks, is a very fragile fish. Weak immune system, prone to deformities. Very slow growing. Nothing like a regular JD. JD are cool fish as well, but they can be major pouters with any change in their environment. Mine sits in his cave sulking for at least 2hrs after every water change. And that's 2x a week for over 5yrs. Even before your decision, I urge you to have a fully cycled tank. Are you aware of the nitrogen cycle and how it works in the aquarium?

 

[Oscar6]

I have had and currently do have both JD and GT. My current male JD is a nasty bugger, I have tried him with an array of tankmates, he fights with everything. Win or lose he is a scrapper. A few months ago I lost another male to old age, and he was the opposite. Great community fish, never bothered anything, big or small. I have never been able to keep JD and GT together, they always fight. All cichlids have their own distinct personality and temperament, you cant just say this fish will go with that fish. Its always a cointoss. You may get away with a school of barbs or tetras, but I don't think you have the volume or footprint to have more than 1 territorial cichlid. My current GT is a 2yr old male, he is in a 265g community that is owned by a giant Oscar. He shows some nuchal hump, but nothing to unsightly imo. I have had male GT that show no hump, single or in a mixed tank. Another of those, "you get what you get" deals. As with any omnivorous cichlid, a quality pellet as the staple, with a varied amount of nutritious treats is a good diet. Hikari Gold is a decent pellet. I use Northfin, not exclusively, but its the main pellet here. I would go easy on bloodworm, imo freeze dried krill is the better offering.