Hybrid Sunfish

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uconn fishhead
Hybrid Sunfish

Hi, Just a caution that people should look closely at their sunfish before nailing down an ID.  Species in the genus Lepomis readily hybridize.  Often the hybrid is more agressive and larger than is typical for either parent species.  In Connecticut, we have 4 Lepomis species (Bluegill, Pumpkinseed, Redbreast and Green) and I have seen all combinations of hybrids in nature.  Below are 5 of the possible 6 combinations between these 4 species.  See how many you can get.


Susquehannock's picture
Hybrid Sunfish

These are drastically easier to ID if you have some context, meaning knowledge of the season in which the fish was caught and what species exist in the water that they came from. Multiple pictures also help.

The other thing is, hybrid sunfish tend to be fertile, meaning that you can end up with fish that are genetic soups comprised of several species. This makes it difficult to come up with a precise combination, even for biologists.

I'm assuming based on the background of these pictures that these were caught in the winter, presumptively in a place that contains all four species. So here are my best guesses: 

1. Redbreast x bluegill

2. Pumpkinseed x bluegill

3. Green x bluegill

4. Pumpkinseed x green

5. Redbreast x green


uconn fishhead
Good job

You got them all.  Most of these fish were likely electrofished during the spring.  I'd have to look them up.

The background is a light blue Rubbermaid bin lid.  Any dirt or smudges were blurred out.

In MD we have those 4 plus

In MD we have those 4 plus the redear, adding yet another layer of complexity to some of the hybrids. Those are great representative photos

Dr Flathead
Dr Flathead's picture
Those are some really crazy

Those are some really crazy hybrids.  Never seen some of those combos before.  I would have said the first one was a Pumpkinseed/Redbrest hybrid minus the red on the ear flap. And the second was a pure Pumpkinseed, just a pale one.  I agree with the last three.  Cool collection of pics!

uconn fishhead
Numbers One and Two

The reason there's no pumpkinseed in fish number one is that the opercular flap is dark to the edge.  Bluegill and redbreast flaps are dark to the edge.  Pumpkinseed and greens have a light margin that will show up in the hybrids.

Photo number 2 is the most common hybrid in CT mostly because bluegill and pumpkinseed are the most common species here.  It has no redbreast or green in it because the mouth is too small and the anal fin margin is not light (the green giveaway).

My first tip off for this one is that the head is shaped more like a bluegill than a pumpkinseed (see photos below).  Also, the pumpkinseed always has those speckles - this fish just has "confused" bars.

tom's picture

These are awesome. A good reminder that natural spectrums of variance within a genus are often seamless. (we assign them taxonomic names, to nature they're just fish) I didn't know hybrids could be fertile. You'd think any 2 that can successfully hybridize past F1 would be funtionally considered the same species. Something to chew on..

iliketofish's picture
Something to chew on

Interesting thread. Nerdy stuff like this one are why I like this site.

Tom as to your point - it depends on one's definition of a species. I've wondered that since I was in college and my biology class tought that if two critters could make fertile offspring they were the same species, but my summer job that same year showed me that rainbows and cutthroats were different species even though their F1s happily make F2s and F3s....  The Bio 101 definition of a species is just overy simplistic is all, and this thread illustrates a good example of why.


I've also wondered why there are hybrid sunfish populations in some places and not others. Over here in Washington we've got plenty of lakes with both bluegill and pumpkinseed (all introduced obviously), but I've never seen a hybrid of the two. Probably just not looking at them close enough I immagine. Makes me wonder though.