they are clearly getting bigger about 1/2-3/4" mantel length. I only see one occasionally but disperse small pieces of frozen thawed shrimp daily and let them get it themselves. No idea how many are in there still, kind of like if you see a mouse in your house you can assume there are more there, BTW my wife saw one mouse in our rural house the other day so I set up 40 snap traps, got 20 the first night 12 the second