Unknown Pond Fish Discovered, Need Id

Somphongsi

Hello!

I have a pond where I keep only Koi Fish. Sometimes, herons, ducks and random birds bring eggs of other fish to my pond. Therefor, sometimes I find baby fish that are not Koi in my pond, but they do not survive, as my Koi tend t0 eat all of them. (there are almost no hiding spaces for small fish) However, this morning, I discovered a fish in my pond that does not belong here. It is not a Koi, and I am unable to identify what it could be. The fish has a very weird pattern, unlike any fish I've seen around here before (I live in Luxembourg, Europe) Any help would be appreciated. I was, unfortunately, not fast enough and only managed to snap 2 pictures of the fish, unfortunately not in good quality. I wanted to take better quality ones, but the fish saw me and swam to the bottom of the pond and didn't come back up. The fish is relatively small and was definetly under 10 cm (under 3.9 inches).

Kind regards, David
 

James17

Really hard to see, kind of from the top, bad angle.
 

Somphongsi

I am going to try to get more photos at daylight tomorrow. I hope I catch it from a better angle. Not so easy due to its small size, and it is very fast and active.
 

James17

Welcome to Fish Lore by the way.
 

TwoHedWlf

My money($.02 internet dollars) is on it being a koi. The dorsal fin looks about right, the patchy color. I can't see the shape of its mouth or barbels or anything though.
 

chromedome52

Looks to me to be some sort of Cyprinodont. There are Killifish species distributed around the Mediterranean, but something close to 10cm would be unusual.

Looking forward to more pictures. Welcome to Fishlore!!
 

Somphongsi

Thanks for the replies! I didn't express myself correcty, but it is definetly under 10 cm, I would say it is approximately 5 cm. (1.96 inches) I will try to get better photos tomorrow.
 

Kasshan

agreed, I looked at and compared pics of pupfish, chromedome52's guess looks to fairly spot on, I concur. as for exact species I would be ignorant.
 

Anders247

It reminds me of a fathead minnow.
Yeah, I believe that is what it is, look at this pic of a fathead minnow:

I think it is a match.
 

chromedome52

I don't think Fatheads have been introduced in Europe, and OP's pond is in Luxembourg. Besides, the subject fish has a square tail, and fatheads have a forked tail.

ID on a fish native to a part of the world that I am not that familiar with is very much a game of guessing. However, I see characteristics that are common to Cyprinodonts. There are a great many species of Cyprinids in Europe, as well, and I do not have a source for keying out ID of European species.
 

Anders247

The tail does appear to be rounded in the picture but it could just be the angle? I think to ascertain that info we'd need a better picture.
 

MikeRad89

Ascertain. 11/10 word choice.
 

TwoHedWlf

It reminds me of a fathead minnow.
Yeah, I believe that is what it is, look at this pic of a fathead minnow:

I think it is a match.

I think your guess is definitely in the lead.
 

Somphongsi

Thank you for all the helpful replies!

I managed to get another picture. Unfortunately, the fish is so small and so fast, never staying calm in a spot. It makes taking photos very difficult.

Edit: After trying for so many hours, I just can't seem to get any good photo. I will add an enhanced version of the last photo.

I hope this is of any help!

Kind regards, David.
 

Anders247

It does look like it has a forked tail to me, but it's not 100% clear.
 

Somphongsi

Good News!

It took me the whole day (in summer heat) and it definetly stressed the fish, making it appear more pale, but after many hours, I caught the fish, took 2 photos and released it back into the pond.

Here are the photos:

View media item 236018
View media item 236019
I hope that my effort paid off, and that this makes identification a lot easier!

Kind regards, David
 

Anders247

Definitely a fathead minnow, in my opinion.
 

chromedome52

It does look more like some sort of Cyprinid, but as I noted, Fathead Minnows are not native to Europe. Need to look for some references on European fish species.

Well, the only book I have with European Cyprinids listed is the Baensch Atlas. I use the Photo Index to narrow down the possibilities, and I found some very interesting photos of Eurasian Dace, Phoxinus phoxinus males in breeding color. Not a perfect match, but a better match on the color pattern than the American Fathead. Head and body shape of the two species is also quite similar. Considering that this species is widespread throughout Europe, and is currently in breeding season which would explain the color pattern (and possibly the hyperactivity). They lay up to 1000 adhesive eggs on rocks, so a bird walking through their breeding area could have easily picked up some eggs on its feet. (There's an old theory brought back to life!)

Was so hoping it would be Aphanius anatoliae, but alas, no good match there.

Edit: Just saw the out of water photo, it does look a lot like a Fathead. Perhaps they have been introduced in some areas of southern Europe? Surprising, to say the least. Would have been a long trip on a bird's feet from the USA!
 

Anders247

But the fathead minnow has been introduced to Europe.......so it can't be crossed off simply because it's not native.
 

chromedome52

But the fathead minnow has been introduced to Europe.......so it can't be crossed off simply because it's not native.
Only question I have left is: Why was it introduced?
 

Anders247

I don't know. Can you tell me?
According to this:
It is introduced in France and Belgium, which is right next to Luxembourg.
Fishbase also says it was introduced to Europe: Pimephales promelas summary page
 

Discusluv

Ascertain. 11/10 word choice.
Unless your an English Lit. grad student, I think I used ascertain yesterday, LOL! I love "ascertain"!!
 

Anders247

chromedome52 just found this article for you:
I think it will answer some of your/our questions.
 

Somphongsi

Big Thanks to everbody for the answers!

Quite a surprise for the fish to be from overseas, I didn't expect that. But since there seem to be wild populations of this species in Belgium, it seems very likely that it was introduced to my pond trough birds, as Belgium happens to be right next to me. Maybe some people also released them into nature, as they are sold as aquarium fish, and birds and herons (which unfortunately visit me quite often) did the rest of the job.

Since they seem to be able to populate new waters randomly, maybe their introduction wasn't such a good idea. I bet there's populations of these all around Europe that haven't been studied yet!
 

chromedome52

Actually, the question was rhetorical, but that article was very interesting. Looked like it was intended to be a slide show.
 

chromedome52

And let it never be said that I will not admit to my errors even if slapped in the face with a Fathead Minnow. ops:
 

TwoHedWlf

Only question I have left is: Why was it introduced?
Why is anything introduced anywhere? There were societies that went around intentionally introducing exotic species in places all around the world for the enrichment of the local wildlife. Here if you find a fish in a local stream it's more likely to be an introduced fish than native, see a bird? Probably introduced.
 

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