Hybrid Sunfish

9 posts / 0 new
Last post
uconn fishhead
uconn fishhead's picture
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
uconn fishhead's picture
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
uconn fishhead's picture
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.



uconn fishhead
uconn fishhead's picture
Those Damn Hybrids!


    I had decided to browse through all the Green Sunfish submissions because, knowing them to be about the most promiscuous sunfish species out there, I suspected there would be plenty of hybrids among them.

    I've resurrected my own forum discussion on hybrid sunfish to bring it to the foreground.  As anyone reading the debates in the last bunch of posts can deduce, ID'ing hybrid fish is a frustrating, daunting endeavor. The difficulty starts, especially with sunfish, with the great variation in appearance inherent within most species.  Then when they hybridize, their DNA gets shuffled like two dissimilar decks of cards (maybe like crossing a standard deck with an Uno deck?) amplifying the possible variation in appearance.

     I have an uncommon personal interest in hybrid sunfish.  I did my thesis on them (monitoring nesting success of F2 hybrids) and have identified thousands of sunfish and hundreds of hybrids during my 39 year tenure as a CT Fish Biologist. I have amassed a sizable collection of photos of CT sunfish including hybrids.

     So what I know for sure about ID'ing hybrids in the field is that it requires an intimate knowledge of the physical variation within any of the possible parent species in a region. Regardless, the other thing I can say for certain about ID'ing hybrids in the field is that no one can ever be completely certain (only with DNA typing can one be certain and who can afford that?).

     So I welcome any reader to call me out because I'm not going to bet any money on any of my hybrid IDs.

     As I mentioned before, I think it's great for members to give their impressions/comments on fish that look weird to them.  If one of us calls a fish a hybrid and the other calls it something else, it adds a footnote to the suspect fish, which alerts readers that there is uncertainty concerning the ID. So, if the reader wants to be sure of what kind of fish they're looking at, they should find photos that have no debates.

     Beyond that, informing a contributor that you think they're submission is a hybrid is mostly just an FYI courtesy.  Our Gatekeepers, in their infinite wisdom, decided to allow hybrid entries to count as either parent species, causing most of the debate over them to be simply academic. 

     So the most important thing we members need to call out on hybrids is whether we think that the animal in question has NONE of the parentage assigned by the contributor.

     I will endeavor to make more lengthy justifications in my future comments on fish ID to aid in discussion.