I am seriously thinking of adding some congos to my 75 gallon tank. I would like to add 8 to 10 but because of the price of $15.00 each (for 2" fish) at the only store I have found them at, I want to make sure there aren't any problems. I have read that they are very fast fish and like a large planted tank. I have that covered. I also read that it is best if they are the dominant species in the tank or they would become shy and reclusive so my biggest concern is their compatibility with my 4 angels. Would their constant movement stress my angels? Would my angels, who are about 3 to 4 inches, spook and stress them? Also, how delicate are they? I have had this tank running for almost 3 years without any problems but I don't want to get something that I will lose or have problems with if I go 2 weeks without a water change.