How to differentiate between Greens and Longears

When I go out sampling, I have been going to a couple of rivers/streams that have both long ear sunfish and green sunfish. How can I differentiate between the two when at 2" or so in length? I am just trying to get photos of a juvie longear, but am overly confused.

When I go out sampling, I have been going to a couple of rivers/streams that have both long ear sunfish and green sunfish. How can I differentiate between the two when at 2" or so in length? I am just trying to get photos of a juvie longear, but am overly confused.

Acquired skill, and I am not that good. Greens have a much larger mouth, and are fairly distinctive as juveniles. They look like a mini green.Longears are a bit more difficult, but if you collect both, you should easily be able to differentiate between the two. Greens will be a bit more fusiform but thicker in width.

Skipjack is absolutely right this is something that will take some time and experience to get good at. Tiny little sunfish are not easy for most people. I have the advantage of having bred nearly every Lepomis sunfish and quite a few others in the family and in doing so I have seen literally hundreds of tiny fish of all these different species and watched them grow up so I have seen them at every stage along the way.

When collecting them just try to get a whole bunch of sunfish at once and work backwards from biggest to smallest trying to place them into groups of the same species. Doing this and doing it often will help a lot. With those two in particular the mouth size is a big help. Little longears are almost round (as tall as they are long) and greens are longer than they are tall. Also young greens often have a reddish hue to the fins and even when very small you can see the thin white or yellow outline to the tail and rear part of the dorsal fin. Longears fins tend to be clear with some small red or brown spots in the dorsal and anal fin when they are really small.

I am in the same boat as NVCichlids when it comes to sunfish. Something I need to remedy.

I can tell them apart, but would have a hard time telling you without showing. Skipjack and smbass hit the nail on the head with how to learn to ID them. When I started working in TPWD River Studies as an undergrad, with no formal ichthyology or formal native fish ID, they would have me take samples on alcohol, line them up from smallest to largest, and then get an ID. It's a great way to look at fish. Just imagine 3,000 Red Shiners lined up from smallest to largest...

I ran into the same problem a lot when I taught ichthyology lab. We taught a trait-based method for field IDs, but if you ask me, by traits alone how to ID a Gambusia, it's still tough for me. A lot of fish you just know when you see them. Like faces.