Mystery fish in my invert QT tank

[wangspeed]

This morning I was observing my QT tanks. One has 7 resplendent anthias about to make it out of copper treatment. The other is a strictly invert and algae tank, or so I thought...

I looked at the invert tank and saw a fish looking back at me. I’m still absolutely shocked! Let’s start guessing what it is. It’s still very young. I’m not sure if this post goes here or in the hitchhiker id forum [emoji14]

 

[cracker]

This is Cool ! Can You get us a better pic?
Just shows UP !

 

[wangspeed]

It must have hitchhiked in on the macro algae. It’s back to hiding. I’ve been watching this tank for weeks now and I haven’t seen this little guy til now.

 

[Maritimer]

Facial profile looks like one of the (many!) varieties of killifish - possibly one from somewhere along the Gulf of Mexico?

Cool li'l hitcher!

~Bruce

 

[GoldeneyeRet]

Cool hitch hiker for sure, but its presence in your quarantine could defeat the qt procedure!

 

[wangspeed]

Cool hitch hiker for sure, but its presence in your quarantine could defeat the qt procedure!

Yeah. He’s definitely caused a kink in my invert QT plan.

 

[GoldeneyeRet]

It's a kinky hitchiker!

 

[Mini Coop]

That is amazing! QT plan foiled or not Can't wait to follow and see what it is.

 

[wangspeed]

It took hours to get this picture. He is super shy and is really tiny.

 

[nereefpat]

Something in the Cyprinodontiformes order...I know there's lots.

 

[wangspeed]

Here he is 2 months later.

 

[nereefpat]

I'm familiar with eastern, and western mosquitofish, and the plains topminnow from school. It isn't specifically either of those three, but it's related.

Maybe one of the universities in florida would be a good start. UF has an extension program.

 

[HKfshkpr1]

It surely looks like a guppy or mosquito fish and they're at home in brackish water. Like mollys that you can keep in a saltwater tank.

 

[Maritimer]

Still say this guy's a killifish. Egglaying, rather than livebearing toothcarp.

~Brucwe

 

[Gareth elliott]

Want to agree with martimer, doesnt have the fin shape or body shape of Poeciliidae.
Looks like a pupfish.

 

[ZaneTer]

Im going with @Maritimer also. Many killifish have the potential to become incredibly beautiful fish when mature.

 

[wangspeed]

Well, I personally have no idea what it is, so we’re all in this ride together [emoji23]

I do know that it must have been an egg laying fish, because the macro algae I bought didn’t have a live fish in it. I didn’t even see the fish for some time after the algae purchase and it was definitely a fry when I first saw it.

I’ll keep updating this periodically.

 

[nereefpat]

It has a couple features that should give it away.

1. The shape of the caudal fin is truncate or even a little indented or concave. Usually, in the order, it's rounded or convex.
2. The dorsal is closer to the head than the anal fin is.

I'm having trouble finding a species in that order with those two features.

 

[ZaneTer]

I suspect fundulus heteroclitus although yours is still very small.

 

[minus9]

It's def a killifish sp.