Green Terror tankmates...

None, just room for the 1 gt in a 50g.

Sand.

You might get by with one smaller cichlid as a tank mate but aggression can always develop over time. Just remember that unless it's an adult the GT isn't going to reach full size over night. If you get several cichlid tank mates, eventually you'll have to get rid of them or buy more tanks.

You can keep a gt in a 55gal with another gt or a dempsey..or any other cichlid that is not small enough to eat.
I would suggest a canister filter for a bigger tank. Hang on filters don't last long with sand in a tank.

Uhh dude, we're not talking about a Red Devil or an Oscar here, GT's dont get THAT big. You can put several other fish in a 50g with a GT. I Have a GT, and Ill list what I have in there with it, granted I have a 125G tank so you wont be able to stock as many fish as Ive got but Im posting my list just so you can see what is compatable with a GT.

Red Devil
Green Terror
2 Jack Dempseys
3 Convicts
14 African cichlids/Mbuna's
Black Shark
Red Tail Black shark
Leporinus

The Devil and Black shark would be too big for a 50G, however, Dempseys do really well with GT's as do Convicts as long as you go with only males so they dont start pairing off. African cichlids work well, and unlike CA/SA cichlids, its ok to overstock africans as it spreads out agression. If you are looking for non cichlid tankmates, those can be tough to find as cichlids will kill most "other" types of fish, that said, Red Tail Sharks and Leporinus are among the few "other" types of fish that mix REALLY well with cichlids. So it just depends on what you want to do. I think you could Get a GT, a Dempsey, a leporinus or a Red Tail shark and several Africans and I think it would look great and work out well for you! Best of luck! I definantly agree that a cannister filter is a MUST!!! And Sand looks WAY better than gravel! Just be sure that if you go with sand, make sure your water intake tube from the cannister filter does not sit very deep in the water, you want to keep it kinda high up, even if you have to rig it so it sits right because with sand, if it is to close to the sand, the filter will suck it up and it will destroy the impellor in the cannister and that would be bad!

I have a Green terror in a tank that started out as a 60 gal in it I had the GT, JD, Convict, Green Severum, and a Jewel. When I upgraded my tank then I added a Nicaranguese, Bucktooth Tetra, Convict. Red Terror and a Green Severum. I have since Pulled out the Severums and Gave them their own tank and will have to Seperate some of the others as they grow. No problems with compatiblity as long as they have adequate territory. Also the aggression levels will jump if there are any male/ female pairs in the tank. The Green Terror tends to rule the tank though and I have even seen mine interfere in face offs between other tank mates. Hope this info helps and good luck.

I would also use gravel as they love to dig

new tank set up

hi guys im new to this site and i thought i would make an account to ask a few questions,

i got my 30g tank set up with gravel/sand, rocks, and atrificial plants

i want it to be a cichlid type of tank but i just dont know how many of these fishes to put in a 30g tank

here are the fishes that i want to put in there,

1 Green Terror
3 Convicts Or firemouth ??
4 African cichlids/Mbuna's
1 red tail black shark

my tank has 4 hiding spots i made with the rocks, i made them look like small caves and also has a plant pot upsidedown so its like a little cave too and i left swimming space at the front of the tank and at the top too, please let me know if those fishes would get along well and good for a 30 gallon tank thanks =]

1 gt in a 55 gal is bare minimum.
If you add other cichlids it will be a war zone.

It could be used for a grow out tank for a few young cichlids, but certainly not for life.

Ask this question over @ MFK & they will back this information 100%.