Yet another thread about frogs/fish/mozzies (+ ID my frogs!)

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caitsith01
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Yet another thread about frogs/fish/mozzies (+ ID my frogs!)

Postby caitsith01 » Mon Dec 03, 2012 4:06 pm

Hi - first, let me say thanks for this forum, which is an excellent resource on building a frog friendly garden.

I'm in Adelaide. I've set up a backyard pond with the following features: mixed depths, shallow areas, mostly native water plants (reeds and a few others), a solar powered pump to circulate water on sunny days and aerate the water a bit, mix of rocks and hiding places.

My goal is to create a habitat for frogs to breed in and generally hang around in/near.

So far, from a frog perspective it's been a great success - I've had some tadpoles in there and the other day I saw my first two frogs. Not sure what they are, but probably banjos or froglets (picture attached - anyone want to ID for me?). Very exciting! I seem to have a nice balance of natural filtration/nitrogen cycling going - repeat testing suggests that everything is reasonably well balanced, pH is fairly stable at a shade below 7, no build up of Ammonia or Nitrite, etc.

However, I have one huge problem: mosquitos.

I've read everything on here about controlling them. A summary of the advice seems to be:

1. Water movement, but not too much because this stops frogs laying.

2. Fish, but only certain native fish that won't eat frogs.

3. Wait for numbers to stabilise and other natural predators to move in.

I am not having much luck with any of these. My estimate would be that in a pond which is maybe 1.5x1 metres, I would have thousands of wrigglers and there are many flying mosquitos visible. This is making our backyard less than pleasant to be in around dusk and after that.

First, I have some water movement, but I am concerned that any more will put off frogs. On top of that, because I've carefully made lots of edging areas for frogs/tadpoles to hide, this creates many little areas where the water never really moves much, and probably wouldn't move even with a full time, more powerful pump.

Second, I have put in some Murray Rainbows. A few died, but one has been in there and alive the whole time (a few months). The little guy just hides at the bottom and never seems to eat any mozzies - certainly, he's not keeping them anything like under control. Despite the claims I've read on native fish websites, he is definitely not feasting on the larvae. I'm not feeding him anything else (he hasn't touched the tadpoles, either).

Third, I have seen no evidence that the mosquito population is going to stabilise or drop to reasonable levels. There are thousands of them, and they aren't going anywhere. I'm not sure what kind of other insects etc would eat them, anyway.

So, after my long winded story - I'm getting a bit desperate. I am loving having a frog habitat, but I can't have it if it costs me the use of my back yard. So what I am wondering is what else I can try.

Any suggestions?

Any other fish which will be less pathetic than the rainbows?

Anything I can add to the water to knock off mosquitos but leave frogs and tadpoles unharmed?

Any other critters or plants I could introduce to attack the mozzies?

Any help would be greatly appreciated...

PS - all of this would be a lot easier if tadpoles just ate bloody mosquito larvae...

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Nick Thorne
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Postby Nick Thorne » Tue Dec 04, 2012 6:19 pm

First, the photos did not seem to appear in your post, so can't help with ID.

As for fish, how big is the rainbowfish? Generally Murray rainbows are very reliable mosquito predators, so I would be checking out conditions to see if there is a reason why the fish is not feeding. Your pH seems fine so it must be something else. What is the water temperature? You mentioned that several of your fish have died - did they die soon after being put in the pond, or what? What is the pond made from? Can you post a picture of the pond, so we can get an idea of the general situation?

Sorry to seem to be conducting an inquisition, but I would like to be able to help you resolve the problem. BTW, I would have thought a single rainbowfish would be sufficient given an approximate size of 1.5 x 1 m. I have 2 in a pond 3 x 2.5 m in Melbourne and they have kept the mossies at bay since a few days after they were put in and that was maybe 6 or 7 years ago. It could just be that you have a fish that doesn't like mosquitoes. Not what I would have expected, but I suppose it's like someone not liking roast lamb (I can't figure that out either, but my uncle is a case in point).

Nick

caitsith01
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Postby caitsith01 » Wed Dec 05, 2012 9:33 am

Hi

Thanks for the reply. I'm not sure why the pictures didn't attach, I'll try again.

The pond is made from flexible pond-liner, i.e., stuff specifically designed for making garden ponds. It's UV stabilised etc. It then contains sand, fine gravel, and larger pebbles/stones (with the intention of creating suitable conditions for biological filtration plus hiding places for tadpoles/frogs).

I'm in Adelaide, so the air temperature since the pond has been in has been in the range of 10-39 degrees. The pond is in a shaded place dug into fairly solid ground and sheltered, and I doubt that the water temperature has fluctuated much.

Regarding the fish that died, I never found any bodies, so I'm suspicious that birds might have got into the first round of fish.

I would be surprised if it is anything chemical, given that tadpoles and frogs seem happy in the water and repeat testing has found no buildup of anything harmful. As well as the wrigglers there are some water boatmen happily flipping around in the pond. There's never been a bloom of algae, just a light coating here and there.

The fish which has been in there the whole time is maybe 5cm long. The new ones I just added are about 3-4cm long. So in total there are 5 at the moment, yet still thousands of wrigglers!

caitsith01
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Postby caitsith01 » Wed Dec 05, 2012 9:38 am

Upload form for the forum isn't working for me, so here's a link to a picture of the frog:

http://postimage.org/image/7ymhp9wcx/

I don't have a pic of the pond handy but will get one in due course.

lolita1
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Postby lolita1 » Fri Dec 21, 2012 11:04 am

No real idea i've got 3 pacific blue eye in 1m x .5m area & some times the only way i know they are still alive is the lack of mozzie wrigglers. Even my 6 tiny babies are doing a great job in their pond.

May be u just have an over load of mozzies so the fish cant keep up?

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Nathan Litjens
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Postby Nathan Litjens » Tue Dec 25, 2012 11:37 pm

Hi,

This is such a common question, and Dave (Jet) Black was pestering me ages ago to cover this topic in article format, so please have a look at the (almost) finished product (minus 2 pictures)

http://www.runwildtv.com/how-we-do-it/introduction-to-frog-friendly-fishes/


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