I have a backyard pond that has a clay bottom and fills up with water about 2 to 4 times a year. I have to transplant mosquito fish (minnows) into it to eat the mosquito larvae. I live in sub-tropical south Texas. I was wondering if there was a Killifish breed that would reproduce there and keep the larvae in check. Any help appreciated.

!Accident

What part of the country you live in? Local killies, if legal, are often best for a pond and cleaning out mossies.

Gambusia are native to a lot of the country, but have been known as damnbusia because of their ability to eradicate the eggs and fry of local species before going for the mosquitoes. The generic eastern Gambusia are responsible for the extinction of at least one (formerly) rare Gambusia species in Texas.

Speaking of Texas, a bunch of years ago a guy came on a mailing list and asked a question similar to yours. It turned out that he lives a little north of Dallas and not too far from the habitat range of the impressive Fundulus zebrinis. Also near by was the legal-to-have Red River Pupfish, Cyprinodon rubrofluviatilis. Not as desired by hobbyists as some other pupfish, they are amazingly tough. If he found some, we urged him to keep track of where they were collected. Rumor has it that Cyp. rubrofluviatilis may be split into two species.

Have no idea where you are from, but obviously killies native to a region are a good starting point. A number of tropicals can be kept out in the summer in many places - if they are not too hot. On the killietalk mailing list Aphanius species have also been promoted as being great for ponds (with winter heaters in the Great Lakes region).

Of course, you can keep that pond with water all year? Or transplant them to tubs? :)

Not trying to get too personal on the Net, but as an example I'm from the Southern 'burgs of Chicagoland.

Southern Tip of Texas- Sub Tropical. Very mild winters.
Pond does dry up, but could be kept full if need be.

!A

I would be inclined to keep it full and with some surface plants if I had killies in there. Is it legal to keep water Hyacinth or water lettuce? It is said that early killie keepers, of the post Victorian crowd, began letting killies spawn in the roots of those plants. That continued where a person had enough light to keep those plants going (or was lucky enough to live in a region like yours where they could keep some of those plants in a pond all year long.

If you were to read about the soils where annual killies are found, it might be interesting to see if there were similarities with yours. I would guess they wouldn't match up. Most mosquito related efforts to stock annual killies, have not been successful. But it would be interesting to make comparisons.

Google pond liners and see if one of those would make keeping that pond going easier for you. You may have to if the water table is seasonally supporting that pond, but drops when it gets drier.

On the other hand, I recall reading a pond article where the author suggested that if a (forest pond) represented an emerged part of the water table, there was a remarkable daily exchange of water with that table. Also, there would probably a terrific, widespread culture of beneficial bacteria in that pond bottom. That writer then took pond keepers to task, by pointing out that they could never expect such an efficient system in an artificial pond because it was separated from the larger world.

There is something of a tension for pond designers. They want the pond to get some sunlight, to encourage the flourishing of plants. But they don't want the pond to cook or become overwhelmed with algae. Around here, if I were to have small fish in a small pond or "container pond," I wouldn't want sun on the pond because the reflection to the sky may attract predatory insects, that either lay eggs or even settle in.

But that is another set of issues.