Fish for greenhouse question

[littlefrog]

I guess this is the right place for it... As part of my greenhouse rebuilding project I installed two long and shallow 'ponds' under my benches in the greenhouse. For thermal mass, mainly, although in a crisis I might tap them for watering needs if I run out of the good stuff.

The 'ponds' are two cinderblocks high, with pond liner so they will hold water. They run most of the length of the greenhouse (one is 36' long, the other 42'), and they are about 3.5 feet wide. Maybe 14" of water depth. One of them actually sticks out several feet from the end of the bench, so that I can grow a few pond plants in actual light, but the majority of the pond surface is under my benches and has an opaque cover (sheets of 1" foam insulation, cheaper and lighter than plywood) to keep most of the plant debris out.

That is the background. But I need a few fine fish for a couple specific purposes. One, algae control. Two, mosquito control. I can already see the mosquitos breeding, and I'd rather not be swatting them all winter. So, I'm seeking recommendations from you fish people. I need fish that will take 55-60F in the winter, require minimal maintenance (I can feed fish but I'd rather not do it often), and don't need a lot of light. Oh, and I have to be able to find the fish for sale somewhere, that is important too!!!

Any fish experts want to help me out?

[Tindomul]

1 name.
Gambusia affinis. The only one I know that will fulfill all your requirements. They will eat everything. Their common name is mosquito fish for their particular liking of mosquito larvae. They will munch on algae, etc... the only problem, they eat everything! They'll leave your plants alone so long as the pop is low enough and food supply is good. Also, if you ever have frogs breeding in your pond, they will eat frog eggs/tadpoles. Don't know if you are interested in that sort of thing. Also, this fish is dirt cheap. They are normally sold as feeder guppies, as they are cousins to guppies they look almost the same except they are drap grey in color. And bigger.

On bright note, you might want to look into Glo fish
GloFish® Photos
I have some and they are soooo cool. Don't know if they will survive cool temps you describe, but they like to eat live fruitflies on the surface of the water. Mosquitoes don't stand a chance! Plus they glo in the dark in the presence of a black light, or in polluted waters.

[flhiker]

I was watching a Dirty Jobs episode where the host went to Louisiana and helped a guy control mosquito's in back yard pools (that have been abandoned) and they where adding fish to eat the larvae. It could be the same fish Tin suggested

[Gin]

I just added a small pond in my greenhouse glad you asked about the fish , it gets quite a bit of light almost the same Temps. a little higher .. 65 at night . Gin

[Charles]

I was thinking dish soap. You use it on the plants anyway. Right? It kills the mosquitoes and the larva. They can not land on the surface and the larva can not get their little air suckers through it. It clogs up their snorkels.

Unless you really want fish. Dish soap.

[dougd]

I would recommend Carp for the algae and mosquitoes. Koi are in the Carp family, but there are specific algae eaters, not sure of the name. Also try Talapia. They are farm raised as well. Research aquaculture.

[dave b]

To keep it simple, buy a few comet gold fish. Theyll survive you winter temps just fine. Theyll survive real winter temps in outdoor ponds.

The mosquito fish have been used in various states as mosquito controls. They would even air drop them into lakes, ponds and swamps. If you try using guppies that do look similiar, they may not survive the lower temps.

[kavanaru]

As Dave said, comet gold fish are excellent for your needs. They are very adaptable and quite easy to keep without much care. They also look nice They are used in the greenhouse "ponds" in the botanical Garden in Heidelberg (Germany) and they do a very good job there

I would not use dish soap. It kills the moskito larvae indeed, but it can create an algi-boom during the summer time...

[DelawareJim]

Goldfish. Guppies won't survive the 50-55'F in the winter and Gambusia are being considered for listing as an "invasive species" in some States.

Comets or feeder goldfish would be your best bet. You can usually get them at a pet shop for about 10 for a dollar or two. I use them in my small ornatental ponds for that very reason.

Koi get too big, they can get up to 3 feet long and need good quality water with a high oxygen content which means adding an airator, and periodic water changes.

Tilapia, a South American cichlid, is also higher demand. You will need to feed them regularly.

No matter what you decide to go with, I would suggest partial water changes which can be done fairly easily by dipping out some water to water plants with and adding fresh to the troughs. The fish water will be a good natural fertilizer for the plants too.

Cheers.
Jim

[kavanaru]

Originally Posted by DelawareJim

Tilapia, a South American cichlid, is also higher demand.

Hi Jim, just a small correction Tilapias are african cichlids... even if they are produced in masses in South America