Not sure on size, my pair was about 3" each when I donated them to a fellow aquarium keeper. They WILL eat anything that does (or doesn't) fit in their mouths. I bought 5 assorted african cichlids (I know, don't hate I was a noob) that were about 1" - 1.5" long, and woke up to find 3 left the next day, with 2 FAT bumblebees. My pair did seem to "cuddle" on each other in a corner though.