Strange happening in my ponds; paradise fish;

[blacksmith37]

I have an 800 g pond and a 250 g pond ( plastic tub ) , various plants . A few big koi ( 5 # ) and a bunch of giant danios and maybe some zebras ( they spawn in a small stream on the big pond , the giants are crowding out the zebras ). Also black mollies in the small pond. I have been using a fish trap to try to catch some green and diamond back water snakes ( got one green so far) .. But I have caught 3 young paradise fish ( 1 ") , 2 from the big pond and 1 from the small. I bought 4 paradise fish this spring, they are in a 29 on a deck, have not spawned, - not over the pond. I can't guess where the small paradise came from . I raised paradise 15 years ago , i don't remember putting them in a pond ( but i am old ).
All the fish winter over in the ponds in Huntsville .

[blacksmith37]

Nevermind . Looking at the 3 young paradise with the 4 adults, I saw a few more young fish. They had spawned and I didn't notice. I have netted duck weed off the surface a few times and put them in the ponds for the Koi to eat. I must have scooped up baby paradise with the duck weed , So, no aliens involved.

[Roshan8768]

That is a fun mystery haha, all part of the fun of keeping fish outdoors! I had a question about your giant/zebra danios, mollies, and I believe you had previously said you have green swordtails? How do they overwinter for you? Do you heat or insulate the pond in anyway?

[blacksmith37]

I have not seen swordtails in a couple years, and there are many giant but few or no zebra danios. I cover 75 % of the top with styrafoam panels below about 50 F at night. My biggest problem is water snakes (eat fish ,so I guess it is the fish's problem . There are garter snakes , black with blue longitudinal stripes that are most common.

[mredman]

Please send photos of the ponds.

Mike

[blacksmith37]

Follow -up : The danios are eating the duckweed before the koi get it. I was swishing the net with duckweed in the pond, when I pulled it out , a very large female paradise was in it , no doubt she wintered in the pond. My next trick is to learn how to put photos here.