This is a very interesting topic. In May 2011 I finished a 1/3 acre put-and-take pond.
It is for HBG, CC, HSB and some RES, I tried trout two winters ago, but couldn't get them out because the other fish were so much more aggressive at taking bait and lures.
Anyway, I've mostly been hand feeding all three of my ponds this season so I can see what my fish are looking like.
Interestingly, I've noticed that the catfish in the put-and-take pond have two distinctive mouth shapes. It is easy to see when they go into their "vacuum cleaner" mode of sweeping the surface for pellets with their gapes wide open. I've put batches of 25-each, 4-inch CC, into the pond each season since May 2011. The 2011 class is now about 18-22 inces. The 2014 class is 8-10 inch. I don't see this year's class eating yet.
The thing I've noticed is that some have a wide flat gape, while others have a smaller almost-round gape. We'll start harvesting some of the larger ones starting next week. It will be interesting to see if I can sex them based on their gap.
I've not noticed this in my BG/LMB/CC/HSB pond, but I will start to look for it now.
Ken
