yes
I would think so.
Jack Dempsey or Tiger Oscar
No, a JD needs at least 45 gallons
Im not sure about the green terror but with the Oscar and maybe jack dempsey as long as your fish isn't full grown (10-14 inches) then it will probably be fine
Oscars get extremely large so I would suggest something at least 180 gallon, but 250-300 would be better.
A Jack Dempsey fish is a popular freshwater aquarium fish known for its striking appearance and aggressive behavior. They are native to Central America and are named after the famous boxer, Jack Dempsey, due to their aggressive nature. These fish require a large tank with plenty of hiding spaces and are best kept with other robust and similarly sized fish.
About a 20 gallon tank.
A small bottom feeder like a dwarf shrimp or a small snail would be suitable for a 5-gallon tank.
you could probably get by with it but if you are going with a blue Texas cichlid and a jack dempsey cichlid in the same tank there will be some rivalry because they look very similar. (jacks don't like fish that look like them) i don't know much about Texas cichlids, if they are territorial you want to go with a bigger tank. Jacks are VERY territorial and will kill anything to claim its fishtank. Hope this helps! :] by the way, both cichlids prefer 55 U.S. Gal + you could get by with them together, make sure that the jack is smaller also otherwise if its bigger it might kill your Texas cichlid.
His name is Tank Dempsey
That depends upon the species of sucker fish. There are several of them. I would not be putting anything other than similar sized Amazonian Cichlids in with Jack Dempseys. They are not 'Community' fish. A Jack Dempsey tank should be no smaller than 30 gallons for 2 fish.
Depending on the size and age of your beardie. For a baby it can be housed in as small as a 10 gallon fish tank For an adult no less then a 40 gallon fish tank