Gymnogeophagus?

Hello, to all.
I have visited this place many times over the past 5 years. You folks have shed much light on my curiosity of fish. I am still a complete novice and have not kept many fish for very long. I usually end up trading them in after a year. I've always been much more drawn to turtles and amphibians. That being said, I am a fan of American Cichlids and plan to keep a few for the long haul. My largest tank is a 75 gallon. Realizing that no S.A. mix has worked for me for more than a year, I am now growing a single Gold Saum from 2 inches current length in this 75 gallon. I may end up growing this fish solo in my 50 breeder instead.
I also have a 20 gal. long with a 3" albino bristlenose pleco and a tiny 3+" albino bichir. I've had store credit at my local shop for a few months so I went to get food. I saw this little Geo (labeled Geophagus sp) and couldn't resist. It's about 2 1/2". It was in a 12"x12" cube with about 30 assorted gourami and tetra mix type fish. Along with another Geo that looked just like it but was getting beat up by the one I bought. This one was also pushing other fish away from it's spot at the front of the tank. My guess, waiting for food. So, I bought it with my credit to put in this 20 long. It shows no aggression toward these other 2 mentioned fish. I didn't think it would because of the completely different appearance. It doesn't even mess with the few feeder guppies and they're tiny baby guppies. This fish is not shy. It sifts the sand non stop, stays in front of the tank, and takes the nls, spirulina and carnivore pellets great!!
I'm realizing that I really have no clue what type Geo this is. From pictures, I think it may be a Gymnogeophagus type? If anybody can help, that would be great. I'd like to know what species it is in order to keep it happy and healthy for the long term. I really want to do what's best for the longevity of my fish. I could see this fish in the 75 gallon with peaceful community fish?
In closing, thank you for any help. Feel free to encourage or criticize. I'll now try to post the pics. I hope they work, and sorry that they suck in quality.

2 more quick night time shots, if it helps. This fish didn't even flinch from the flash...just thought it might get more food out of me.

Thanks. It may look beat up from the pictures?? But, all I see is a belly that should be thicker. It has no visual issues besides that. All fins and scales look perfect. Am I missing something? As I said, it was in a small, packed tank at the shop, but it was the bully. And neither the b.n. pleco nor the tiny one-eyed bichir that i have with it are being aggressive.

^ Thank you for your input as well. I was guessing female from my crude understanding of rounded fins. And the lack of color at 3". I'm surprised that I came far enough on my own the question the infamous (Geophagus sp.) label that it was sold under. It's doing great so far after 4 days.

Thanks, notho2000. It does resemble that picture the most. Thank you all for your help.