Baby Fish ID

[Dog Whiskey]

I live on the Back Bay in Biloxi, MS. We have sail-fin mollies in brackish ditches and bayous around here. That looks like a baby. They’re live bearers and live in full fresh or full salt water. They are not as colorful as the ones at the LFS, but the males do have lots of color

Yea the shape of the body right at the tail is what made me think molly. It’s hard to judge from the pics though, and I could be entirely wrong.

I've had sail-fin mollies when I had a freshwater tank and I agree it has some similarities. But it's dorsal fin isn't as large (at least what I can see). And I'm still baffled how a live bearing fry could have gotten into the tank -- if it came with the live rock it would be larger by now. It almost makes sense that it's something that came in a larva stage with the rock...

 

[dedragon]

it could be a brackish killifish as well, either way life finds a way

 

[Sharkbait19]

Kinda looks like a killie
The mouth would be more upturned on a molly:

 

[LAA]

Looking for some help. I have a 55 gallon FOWLR. Introduced three blue-green chromis in late December who within a week became two blue-green chromis. The bully was then sent into a breeder box for a couple of weeks.
I also have a pair of juvenile clownfish (introduced in mid-January) who are still trying to sort out their hierarchy.
Mid February I introduced three fish from @Biota_Marine: a radial filefish, a starry goby, and a forktail blenny. I've also introduced some snails and some macro algae and copepods from @AlgaeBarn
So today this dude shows up. NO ONE has demonstrated any spawning behavior. He's about 1/2 inch, blends with the rocks, and appears to be a fish. His dorsal fin is kind of in the position where it would be for a chromis, but the body is less chunky and more elongated.
Any ideas?

Baby Molly?

 

[Dog Whiskey]

I agree, the killifish looks closest. This kind of looks like what it is... but not exactly correct. The bands are more specific and there's more of a belly on the fish in the photos. Of course, these are adults.

Tried to add a video -- dunno if it will play.

 

[Freenow54]

Looking for some help. I have a 55 gallon FOWLR. Introduced three blue-green chromis in late December who within a week became two blue-green chromis. The bully was then sent into a breeder box for a couple of weeks.
I also have a pair of juvenile clownfish (introduced in mid-January) who are still trying to sort out their hierarchy.
Mid February I introduced three fish from @Biota_Marine: a radial filefish, a starry goby, and a forktail blenny. I've also introduced some snails and some macro algae and copepods from @AlgaeBarn
So today this dude shows up. NO ONE has demonstrated any spawning behavior. He's about 1/2 inch, blends with the rocks, and appears to be a fish. His dorsal fin is kind of in the position where it would be for a chromis, but the body is less chunky and more elongated.
Any ideas?

Maybe happened in the store. The bully caught his wife fooling around

 

[dedragon]

Maybe happened in the store. The bully caught his wife fooling around

Oh no! dont take it out on the kids though rofl

 

[fish farmer]

Looks like a killifish to me, gulf or rainwater?

 

[Dog Whiskey]

So baby fish update: it's still hanging around the rocks but is venturing into the main water of the tank. It's cool becuase the color changes slightly depending upon where it is: more beige when by the sand an greener when near the rocks.

It is FASCINATED by the forktail blenny, often following it around the tank like an annoying little brother or sister. So far the blenny seems pretty chill about the whole thing, probably because it's trying to become a part of the chromis gang.

Best guess is that it is a killifish. But it's eating and growing. I've been calling it Lagniappe.

 

[Cary Hover]

Looking for some help. I have a 55 gallon FOWLR. Introduced three blue-green chromis in late December who within a week became two blue-green chromis. The bully was then sent into a breeder box for a couple of weeks.
I also have a pair of juvenile clownfish (introduced in mid-January) who are still trying to sort out their hierarchy.
Mid February I introduced three fish from @Biota_Marine: a radial filefish, a starry goby, and a forktail blenny. I've also introduced some snails and some macro algae and copepods from @AlgaeBarn
So today this dude shows up. NO ONE has demonstrated any spawning behavior. He's about 1/2 inch, blends with the rocks, and appears to be a fish. His dorsal fin is kind of in the position where it would be for a chromis, but the body is less chunky and more elongated.
Any ideas?

Pretty cool and way small. Couldn't see it until got to your arrow. Cute little thing.

 

[Duncan62]

Looks like a gambusia which is a livebearer and would live in saltwater

Guppy. Lol

 

[vetteguy53081]

Guppy. Lol

same family

 

[bnord]

Looks like a gambusia which is a livebearer and would live in saltwater

you really seem to know your elbows from your ankles.... respect

 

[Jay Hemdal Verified Community Expert]

So baby fish update: it's still hanging around the rocks but is venturing into the main water of the tank. It's cool becuase the color changes slightly depending upon where it is: more beige when by the sand an greener when near the rocks.

It is FASCINATED by the forktail blenny, often following it around the tank like an annoying little brother or sister. So far the blenny seems pretty chill about the whole thing, probably because it's trying to become a part of the chromis gang.

Best guess is that it is a killifish. But it's eating and growing. I've been calling it Lagniappe.

My guess is a killi that came in as an egg attached to some macro algae. Contact Algae Barn, they may keep killis in some of their propagation tanks. I’m thinking Fundulis similis….but that’s just a guess.
Jay

 

[Dog Whiskey]

My guess is a killi that came in as an egg attached to some macro algae. Contact Algae Barn, they may keep killis in some of their propagation tanks. I’m thinking Fundulis similis….but that’s just a guess.
Jay

Thanks, Jay. That's a good thought -- I need to get some more pods from them so that's a great idea!

 

[Dog Whiskey]

A couple of pictures. It's getting really bold. All seven of them were hanging together -- two chromis, two clowns, the blenny, the starry goby, and Lagniappe.

It's hard to see in these photos, but the anal fins are actually red tinted and there's a bit of yellow on the tail.

Whatever it is, it's cool and adapting well. About a inch or so at this point and swimming in open water. Loves the macro algae. It's actually been chasing the larger chromis (nicknamed Bully Bob) around the tank, which is hilarious. So maybe it will turn into the sheriff and keep everyone in check.

 

[Jay Hemdal Verified Community Expert]

A couple of pictures. It's getting really bold. All seven of them were hanging together -- two chromis, two clowns, the blenny, the starry goby, and Lagniappe.

It's hard to see in these photos, but the anal fins are actually red tinted and there's a bit of yellow on the tail.

Whatever it is, it's cool and adapting well. About a inch or so at this point and swimming in open water. Loves the macro algae. It's actually been chasing the larger chromis (nicknamed Bully Bob) around the tank, which is hilarious. So maybe it will turn into the sheriff and keep everyone in check.

Now it looks more like a baby sheepshead killifish, Cyprinodon variegatus.

Jay

 

[Dog Whiskey]

Now it looks more like a baby sheepshead killifish, Cyprinodon variegatus.

Jay

The description sounds right, but it isn't as chunky and the coloring looks a little different from the the pictures I've seen. But the red and yellow seem right.

 

[Duncan62]

The description sounds right, but it isn't as chunky and the coloring looks a little different from the the pictures I've seen. But the red and yellow seem right.

Guppy.

 

[Dog Whiskey]

Guppy.

Yeah it looks a lot like that or a gambusia. Still a mystery as to how it got into the tank if it is a live bearer.