Sure, they love the same water parameters and would all go great in a 5g together.
I hope you get the sarcasim, thats a big negative ghostrider. Umbee and RD in a 300- 400g maybe at full size. Might get away with a 300g if you really stick it.
I have a 360 gallon and can't keep anything with my Grammodes, with a umbee and in a 360 with others I doubt it... although I know each situation may be different, but I doubt it...
I don't know many bookies that would take those odds. You would need a very large tank for a full grown Dovii alone. Mybe a RD and Dovii of opposite of sex raised together from a very young age ie male RD and female Dovii, maybe they would bond by killing the cuda.
tough to say. how large is tank? cichlids seem to be more interested in other cichlids then some oddball. as long as the tank is large and the cuda isnt dinner size then i think i could work. my cichlids dont pic on my oddballs singray and bichirs. id be more worried between the umbee and rd killing each other.
Size tank? Cudas are more of a piscivore fish and would get outcompeted by your two brutes. Cudas are very hard to wean off live meaning you would have to use live food and that is not a good diet for cichlids.
If you really want Cudas get them there own tank-125 gallon with a school of Red Tail and Hujetas would look nice.