8 replies to this topic

[Betta132]

Our neighbors haven't chlorinated their pool in five years, and it's now a pond. Current inhabitants are backswimmers, little black diving beetles of some sort, water stick insects, probably a bucketload of dragonfly larvae as soon as it's dragonfly season, and some sort of large fast diving beetle that I couldn't catch. Current vertebrates are toad tadpoles in all stages, leopard frog tadpoles that are mostly maturing now, and some bullfrog tadpoles. There are no mosquito larvae because they throw those mosquito donuts, the nematode-powered ones, into the pool now and then. 

They'd like to add some sort of small predatory fish at this point, to help keep bugs from going out of control, and I also think predators might be a good idea. They have an enormous amount of tadpoles, which the predatory insects clearly can't catch up with, and I'm sure a lot of slow tadpoles that should have been eaten are morphing out. We're talking several hundred leopard frogs and probably thousands of toads every cycle. Waterbirds aren't showing up to help with control because they have a dog, but the dog ignores frogs. 

The pool doesn't have a running filter, but there's always at least 3-4 feet of water, and it's just about full (10+ feet) right now. Water is pretty murky, but it doesn't stink or have any sort of a foam, and I suspect the presence of healthy tadpoles implies that the water is clean enough for sunfish. Would a few baby sunfish be a good addition, maybe bluegills? There's probably a deep layer of leaf litter and sticks by now, and they can throw in some cinderblocks or bricks for additional cover if it's needed. The aim isn't to wipe everything out, just to add some sort of a predator, so I'm guessing bass would be a bad plan. 

[Michael Wolfe]

Even topminnows would keep your bug and small tadpoles in check.  But sure, small sunfish would work too.  Go for it!

[Betta132]

Is there any species in particular that would work well? Seems like I'd need to find a species that will breed and keep itself established without overpopulating and wiping everything out. 

Blackspotted topminnows look like they could also work, and apparently they're native, but I've never seen any. Where would I find them? Any river in particular in Central Texas?

How about a batch of topminnows and one or two sunfish of species that don't normally crossbreed? That way the sunfish would put a dent in the predatory insects for a few years, allowing the topminnows to breed and hit a fairly sustainable population without their fry just being wiped out in the beginning by all the bugs. And when the sunfish died of old age, the topminnows would be there to take over the bug-eating. 

Edited by Betta132, 30 May 2016 - 02:29 PM.

[gzeiger]

I am confused by the desire to control frogs. I would at most stock something that definitely can't reproduce - preferably one of a species, for example.

[Betta132]

It's not really a desire to control them, per se, just add a little natural selection. Some of the froglets morphing out are slow and don't seem particularly bright, so apparently there aren't enough predators around to keep the slow/dumb ones from making it to froglethood. Flooding a backyard with froglets also seems like a good way to run out of froglet food and starve most of them out. 

I suspect most ponds this size would normally have fish by now, but it's uphill from all other water sources, and there have never been any egg-spreading waterbirds in it thanks to their Lab.

[dac343]

Adding sunfish to the pool will pretty much eliminate any frog reproduction.  Personally, fish empty breeding sites are in short supply even though prior to colonization would have been quite common.  Let it act as a natural fishless wetland.  It may seem counter productive to you to see so many morph out but thats part of being a r-selected species.  Only a small fraction of those that morph out each year will survive (some years none may).  Let it be....

[sbtgrfan]

I agree with David above. I see no need to add fish to elimate frogs or other bugs. You won't flood the backyard with frogs and frogs are also a natural part of the ecosystem. Same with the other bugs. If they aren't hurting anything, why remove them? Let it do its thing and natural selection will indeed occur without human intervention. We as fish keepers tend to see a body of water and think fish immediately, but we should consider other inhabitants too.

[NotCousteau]

I'm a native plant gardener and have been considering installing a fish-free pond for a few years. As dac343 and sbtgrfan noted, fish-free vernal pools, ponds, wetlands, etc. are very important environments for insect and frog reproduction. We need more, not less of them.

I say leave out the fish. Throw in some nice plants, though.

[loopsnj64]

I'm a native plant gardener and have been considering installing a fish-free pond for a few years. As dac343 and sbtgrfan noted, fish-free vernal pools, ponds, wetlands, etc. are very important environments for insect and frog reproduction. We need more, not less of them.

I say leave out the fish. Throw in some nice plants, though.

Water Lilies (Like the nuphar species, I often see those growing in REALLY deep water)
Water Heart (Nymphoides peltata, needs shallower water, but I could see it working)

Reeds
Carnivorous Plants

just some ideas