Yeah, I've had to adjust my tanks many times so that they are comfortable. Crazy things just keep growing...the one with my picassos is huge and the one with my picasso/onyx pair is no joke either. The toadstool that it is in front of in the pictures is probably 6" long and about 4" wide at top, just to give you a feel of size.
The best comparison for the top one is to just tell you that the clowns are about 2.5" and 1.5" each, so the anem would have to be about 7-8" across. The foot(stem) is longer than the head is wide.