Here's a couple of photos to help forum member in identifying bluegill by sex.
This fish was caught yesterday at my all-male bluegill pond. Note the extremely good body condition due to lack of competition and availability of artificial feed. This fish has a large ear flap or ear tab, black in color and extended posteriorly (tailward). Vivid coloration and burgundy colors on breast. Lots of black tips on scales.

Here's a mature female bluegill. It's a large mature fish that is also pellet fed. Much shorter ear tab, yellowy colored breast. No black spots on side scales.

Now here's where it gets a little tricky. This is a smaller fish but is still a mature female with eggs. Still has a short ear tab and yellow coloration on breast.

But this is a mature, smaller male bluegill that may be acting as a "sneaker" or "cuckholder". The coloration is much more drab, the ear tab isn't as big, but he can't quite hide the slightly longer ear tab.



This fish was verified as a male shortly before I ate him. He is using the muted color and smaller stature to be able to hang around Mr. Big Boy's nest without being attacked. When the female moves in to lay the eggs he sneaks out of the weeds and "provides a little genetic information".

Bruce,

Excellent pictures! Did you verify that the cuckholder is actually a male by the black scales? I see some black scales up high up the side of the fish behind the head.

Not trying to disagree with you but isn't that a little big for a cuckholder? Could it have actually been an immature male or one that just has not gotten into the spawning mode yet? Just asking.

I verified him with the "filet knife" method. Yeah, he could be an immature male that just reached seven inches so fast that he didn't mature yet, or because he's around so many big, dominant males. I think in a typical pond a cuckholder might be more likely to be five to six inches, but in the pond this one was caught at there are tons of really big, robust 8-10 inch males.

I like your observation about the black spots, though. I hadn't noticed it until you brought it up, but there they are!

The pond I caught him in yesterday had other males of similar length that were very vivid in color and seemed ready to spawn.

Bruce,

Makes sense.

Are your pond temps coming up yet? We had a hard frost again this morning and I think we are suppposed to have another one tomorrow morning although daytime highs are going up every day from now on.

I was fishing my pond and a friend's pond yesterday and the water temps were a miserable 49 degrees. We've been in the 20's or 30's for lows for like seven straight days now. I'm trying to arrange a bluegill fishing outing this afternoon.

Great pictures and excellent info! Thanks, Bruce.

I'm trying to decide if I want to print these out and laminate them, so I can put them in my tackle box and reference them over and over at the pond. I definitely want to use this info to help decide whether a BG goes back in the water or into the deep fryer.

What Bruce has done here is fail to put the unit of measure on his plastic board.

Come on now Bruce! Those are centimeters right?

Just kidding.

Sunil, I recognize that board from the horse business. It's marked off in hands.

Very nice pictures Bruce ! Years ago Bill Cody sent me similar ones thru e-mail...but his were a lot smaller

Eastland,

Yep, Bill's are never as big as he says they are! Take those perch he was watching through the ice. :p

Right, Theo.

...and horses are a little easier to identify by sex as well, aren't they?

I've never needed pictures with horses, descriptions alone have always been sufficient.

Cattle are even easier.

Bruce :

Great post . What more can one ask for in a post : beautiful { and large} BG , outstanding info and a learning experience . I was aware of the dark vertical bars on BG , the coloration and ear flaps but I did not know to look for the black tip on the scale of the males . The male only BG pond is interesting . Keep us posted on the results.

I occasionaly catch what I think is a BG/RE cross which I assume was a mistake due to muddy water conditions during the spawn or a confused BG cuckholder. I will try to post a photo next time I catch one. If anyone has seen or heard of a BG/RE cross let us know.

What about coloration outside of the spawn ? The BG seem to be more silver and less colored . From watching BG in my aquarium the color is much less vivid outside the spawn. The BG also change color based on conditions like stress , anger, fear. They get much darker when these conditions exist. Thanks -- ewest

A friend of mine, Don Gabelhouse, who is Nebraska's fisheries chief has told me that muddy conditions during the spawn do, indeed promote hybridization of lepomis species.

BG/RES hybrids do occur sometimes in the wild. I think I actually have one in one of my small ponds. My guess is that they grow pretty big if they have appropriate forage.

Both male and female bluegill have more vivid coloration in clear water. Sometimes after a big runoff event, and the subsequent clouding of the water, our bluegill will turn almost silver in color due to turbidity.

Also, stragely enough, bluegill that are transported in dark colored containers are brighter on arrival than those transported in white containers.

Cecil, I checked on cuckholder size and my "source" says that the sneaker males are smaller than cuckholders. A sneaker uses his small size to create opportunity and a cuckholder uses his drab color to do the same.

Hey Bruce!

Due to the Illustrated Condello Method I was able to sex the BG I caught tonight - it matched up quite well with your cuckholder/immature male description and picture (he's now in the freezer awaiting company).

I would probably be posting the picture of this trophy 6 3/4" BG, but my Webmaster is in Washington, D.C. on his 8th grade class trip.

Thanks again for all the info!

You're welcome! Sometime I'd like to get a few more male bluegill photos on to show fish in between that 7 in. cuckholder and the big 8+ inch dominant male.

Bruce :

Thanks for the additional info on BG/RE cross. I think you are correct in your assessment that they may get large. We catch about 1 or 2 of these crosses a year.

In our ponds the RE appear to spawn twice { march and april full moon if temp. is ok} while the BG spawn 4 or 5 times { april-aug.}. Sometimes the april spawn is accompanied by heavy rain/muddy water. I think this is the cause of the crosses. All of the crosses I have seen/caught were about 50 % larger than the large BG in the pond. Most were in the 12 inch/ 1.5 lb range. One in particular looked like a dinner plate { 13 in. and 2+ lbs.}. It was the largest lepomis I have seen. However it was not even close to the state {Miss.) records for BG {3.45 lbs }or RE {3.33 lbs.}. The coloration on all was similar and what you would expect from a BG/RE cross - mixed up and with characteristics of both. Silver/pale green with muted BG colors , no verticle bars but with a BG ear flap and body shape , but spotted pattern like a RE. I did not check to see if any had the mouth { crusher } of a RE.

Thanks -- ewest

Your description of the hybrid is EXACTLY what mine looks like. I've also found that RES seem to spawn on the next deeper shelf or tier than the BG. When I'm fishing pits that have both during the spawn I'll catch the male BG in spawning colors at a certain shallow depth and I'll catch the male RES in spawning colors a little deeper.

Bruce,
This is exactly what I was looking for.
Thanks

Courtesy of Mr. Greg Grimes a photo showing male vs. female differences of both BG and RES.

Both males are on the bottom, I believe.