I was all ready to talk to you about raccoons! haha
The only possibility I can think of is that a bird.....herons?? had their eggs on their feet when they got in your water??

I had fry in the pond for a very short bit, I think they came in with some plants I ordered. The quirky quartet of comets found them though, at least that's my guess.

I wonder if they could be black swordtails?

~dianne

I was able to catch one in a net and take some pictures, you have no idea how long that took :(

He is not nearly as dark grey as he looked in the water. He appears to be a native lake fish of some kind and scares me he may grow large and eat all my comets....

Please help, there are at least 6 that I have seen ranging from 1/2 inch to 2 inches. They all look exactly the same.

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This one you can see his white mask better but it is blurry:

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In my opinion, it looks like a comet goldfish. It's not bass fry of any type but it's not carp either. It's definitely not sturgeon or catfish. I'll stick with goldfish.

I don't know what kind of fish it is, but I do think we need to have a caption contest for that last picture!!

I submit, "Okay, enough with the fun and games. Get me out of here NOW!!!!!"
hahaha
Anne

Can't answer your question, but he is cute. I'd keep them. Years ago a group of bluish grey fish appeared in one of my ponds. From where, I have not a clue unless there were eggs on a plant I bought. These guys are not koi or goldfish and remain the same steely bluish grey color. Very friendly, they eat out of my hand.

It is a young goldfish. It will probably change its color as it ages.
Fish eggs do not travel well unless it from adjacent pools so the bird as a vector is probably unlikely.
If you are looking for different fish other than goldfish for your pool then check the link below. No spam. Just wishful thinking as I used to raise Florida Flag Fish here but have not in a while and keep wondering if I have the time to make a new pond to try. Still have to deal with raccoons though!!

Here is a link that might be useful: Arizona Water Gardens

Goldfish. That bronze or olive color is the color of the goldfish ancestors.

That is a goldfish that most breeders would cull because it hasn't changed to a pretty color.

All goldfish fry don't color up nicely and neither do all koi fry.

They can be that bronzy color to black. Sometimes they are hard to see because they are dark.

Shubunkins hatch with their light base color but the rest of the goldfish varieties hatch blah and then turn pretty. or not...

Thanks everyone, it was suggested previously from someone that he is a short finned common goldfish.

Here is a pic of what most of my fry look like and as you can see he looks much different.

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Yes, it is a short finned common goldfish.

Shubunkins and most koi are hatched colored but the bulk of goldfish varieties are hatched that color or darker.

You might try feeding him Koi food or goldfish food that emphasizes color. This was suggested to me early in my ponding experience, and that's all I've ever fed, and my fish are all colorful. And prolific.

yep goldfish babies...

I'm not sure exactly what kind of fish it is, although like the others I suspect it's a goldfish.

That being said...your 'tank' is a little small. I would recommend moving it to a larger body of water. Otherwise you will have to make frequent water changes. :)

Groundbeef, that is funny. Actually had me thinking about it for a minute. LOL

I sent the pics to my brother who replied "I don't know what kind it is, but I can tell you it doesn't like that glass" to which I replied with "I know I put him back in the pond as soon as I was done taking pictures, besides I was thirsty and needed a drink of water. That is my only clean glass". ;)

Well the silly little masked fish are now a year old and appear to be koi. They have barbs so I think they must be koi. There are only two that made it, but they are by far outgrowing my comet fry from last. Funny that I ended up with koi without even buying any LOL. I had only comets and mosquitofish when these guys arrived. All I can figure is they must have come in a plant or something.

Here are a couple of the pics I posted above that now have broken links.

Fishie last year
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And here he is yesterday. His color has turned kind of an antique gold color. He is very pretty.

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Here he is next to one of the comet fry from last year. They were the same size last year. You can see how much he has outgrown the comet fry. I think he is about 6" long now.

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He/she is beautiful....thanks for sharing the pictures with us.

This is strange, the first 2 pictures to me are Goldfish because of the mouth and the type is Common from the body shape. I mean I'd bet serious cash on it.

But the next 3 pictures are Koi, although I can't really see their mouths. The color, scales, body shape, fins are all Koi to me. Any chance these got mixed up?

Nope, I have been watching these guys grow for a year now. It wasn't until just recently that I started seeing the barbs. They have always been easy to spot because of the white mask they have. Only two of them have made it and the other ones colors are muted compared to this one but they have the same markings.

Here is a picture of his face last year, you can see the same white mask.

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The really strange thing is these guys just showed up one day before I had koi. I bought a lot of plants from places that had koi in with the plants, but none of the koi looked liked these guys. weird.

That picture is kind of fuzzy, but that's a goldfish mouth isn't it?

I agree the first two pics look like goldfish and the second three koi. If they are the same fish they ARE koi not goldfish.

Very hard to tell the difference when they are tiny like they were in last years photos.

Eggs can come in on plants. You would not be the first person to have fish that were never purchased by you.