in my personal opinion, a the tank should be at least 1.5 times the width of the expected adult size of the fish. a smaller, narrower tank can be used as a growout but should eventually be upgraded
Get three larger tanks. Get a 75 gal and get yourself a nice pair of Crypthoheros sp (cutteri or sajica). Or toss the crypthos into a 90g and toss some HRP into to 75. Use the 55 for a colony of Apistogramma sp. .
At this point you will need to get yourself a few more tanks, clear out your basement and start building some racks to hold all your new tanks and more. Build a pond............... Now there is now turning back, you are a MFKer Have Fun!!!
I think a male GT will be a bit cramped in a 55. However a female should do just fine in there. You could also probablly throw in some dithers with her.
There's a lot you can do with a 55. Are you looking to put a single specimen in? A pair? Or maybe a mixture of smaller cichlids?
just add some dithers
or a small pleco or syd cat
dithers ie barbs danios or something i love giant danios quick enough not to get eaten adn they are crazy
dithers can keep the gt occupied and cats and plecs dont get bothered by gts but can fill up space
i was looking for two maybe three cichlids, and i really want a FM, and i kinda decided no on the green terror, but now i was looking for somthing for the FM like a salvini and some dither