We are finishing off a fish pond out in the backyard. There used to be a pond there before, but it was much smaller than this one, which holds 500L of water.

This pond (like the old one) attracts skinks, water dragons and frogs. The frogs lay their eggs there. Unfortunately, so do the mozzies.

Many years ago I researched species of fish which were:

- native to my area
- would eat mozzie larvae
- would not eat tadpoles

The only match was the Pacific Blue Eye, so I bought 10 of them. After a year or-so, they all were gone and I assumed that they had either died from lack of water volume or that they had been eaten.

Now, after a little more thought and research, I have discovered that these fish may have actually died from the cold. Although they are native (even to Sydney), they seem to be found in large bodies of water or in tributories to the ocean i.e. water bodies with large thermal masses.

To get to the point, will a water heater like this work for a pond in the shade, in winter, in Sydney? There is 12V power to the pond.

http://www.theaquariumcompany.com.au/pages/products/product/aa-28watt-heater-converter-12v/

Speedy said:

We are finishing off a fish pond out in the backyard. There used to be a pond there before, but it was much smaller than this one, which holds 500L of water.

This pond (like the old one) attracts skinks, water dragons and frogs. The frogs lay their eggs there. Unfortunately, so do the mozzies.

Many years ago I researched species of fish which were:

- native to my area
- would eat mozzie larvae
- would not eat tadpoles

The only match was the Pacific Blue Eye, so I bought 10 of them. After a year or-so, they all were gone and I assumed that they had either died from lack of water volume or that they had been eaten.

Now, after a little more thought and research, I have discovered that these fish may have actually died from the cold. Although they are native (even to Sydney), they seem to be found in large bodies of water or in tributories to the ocean i.e. water bodies with large thermal masses.

To get to the point, will a water heater like this work for a pond in the shade, in winter, in Sydney? There is 12V power to the pond.

http://www.theaquariumcompany.com.au/pages/products/product/aa-28watt-heater-converter-12v/

might be a bit of overkill.
‘d be more inclined to use a small 12v pump and about 10m of black poly pipe, run the pipe over a patch of ground that gets plenty of sun.
should be able to increase the temperature enough

don’t forget to include areas for hiding. Outdoor fish on a smallish scale are more work than most think. A high mortality rate.

another thing that mosquitoes don’t like is moving water, so a fountain is often utilised.

stumpy_seahorse said:

might be a bit of overkill.
‘d be more inclined to use a small 12v pump and about 10m of black poly pipe, run the pipe over a patch of ground that gets plenty of sun.
should be able to increase the temperature enough

Okay, we already have a 12V pump installed.

Arts said:

don’t forget to include areas for hiding. Outdoor fish on a smallish scale are more work than most think. A high mortality rate.

another thing that mosquitoes don’t like is moving water, so a fountain is often utilised.

There are lots of places for hiding. We have a dog now and her favourite thing is chasing lizards, so this was a must when planning the pond.

We did not have a pump before. Perhaps this pump (which I’ve just calculated will circulate the water every 7.5 minutes) will do just fine.

No fish needed?

Speedy said:

stumpy_seahorse said:

might be a bit of overkill.
‘d be more inclined to use a small 12v pump and about 10m of black poly pipe, run the pipe over a patch of ground that gets plenty of sun.
should be able to increase the temperature enough

Okay, we already have a 12V pump installed.

when mr speedy goes to bunnings, get him to pick up a 25m coil of 19mm Lo-Pol, hook it up to the pump and run it through a sunny patch and back into the pond, best to have the outlet underwater

stumpy_seahorse said:

Speedy said:

stumpy_seahorse said:

might be a bit of overkill.
‘d be more inclined to use a small 12v pump and about 10m of black poly pipe, run the pipe over a patch of ground that gets plenty of sun.
should be able to increase the temperature enough

Okay, we already have a 12V pump installed.

when mr speedy goes to bunnings, get him to pick up a 25m coil of 19mm Lo-Pol, hook it up to the pump and run it through a sunny patch and back into the pond, best to have the outlet underwater

We already have a length of the corrugated black tubing which carries the water up through a gap in the wall to later trickle down the wall. If it’s extended by a few more metres through the garden bed above (which gets plenty of sunlight), it could do the trick.

Just thinking that these fish are not actually needed now. That would be best.

Speedy said:

stumpy_seahorse said:

Speedy said:

Okay, we already have a 12V pump installed.

when mr speedy goes to bunnings, get him to pick up a 25m coil of 19mm Lo-Pol, hook it up to the pump and run it through a sunny patch and back into the pond, best to have the outlet underwater

We already have a length of the corrugated black tubing which carries the water up through a gap in the wall to later trickle down the wall. If it’s extended by a few more metres through the garden bed above (which gets plenty of sunlight), it could do the trick.

Just thinking that these fish are not actually needed now. That would be best.

corrugated isn’t as good for absorbing heat as the smooth stuff, and if you want it heating the water, you don’t want it trickling at all

stumpy_seahorse said:

corrugated isn’t as good for absorbing heat as the smooth stuff, and if you want it heating the water, you don’t want it trickling at all

So smooth it will be, if we need it. Will the trickling make it lose more heat?

I think we will watch for mozzie larvae with the pump in use. Only if we find some, we’ll revisit this fish/heating thing.

Speedy said:

stumpy_seahorse said:

corrugated isn’t as good for absorbing heat as the smooth stuff, and if you want it heating the water, you don’t want it trickling at all

So smooth it will be, if we need it. Will the trickling make it lose more heat?

I think we will watch for mozzie larvae with the pump in use. Only if we find some, we’ll revisit this fish/heating thing.

yes, trickling will make it lose heat.

Good luck with it and keep us updated :)

While Pacific Blue-eyes can survive massive salinity changes (from fresh to double strength salt) they only like water temps down to 20 degrees. Your native rainbowfish, however, can handle down to 10 degrees. Rainbowfish are just as good, if not better, at mosquito larvae prevention so you only need one or two.

Pro tip: Get a few rushes and other plants from a local swamp or even roadside ditch in a pot to put in the pond – the mud/soil will seed the pond with all the best critters and bacteria.

Wot CS sed, get rainbow fish and forget the heater.

you could have water enter a black panel to collect the sun’s energy

you might need to have a deeper pool to retain heat? less surface area to allow water to cool off

you need a temperature sensor

i would buy a small ardunio and write a programme that looks at water temperature and turn on a pump to a panel (or have a separate system to collect energy)

you could even set up an alert system if the water temp falls to a critical level

have a grill to stop birds attacking the fish

I have no mozzies in my pond, lots of other life though, water Beatles, water. Boatmen, dragonflys, frogs, two fat goldfish and lots of little fish whose eggs must have come in on water plants and I found out are known as freshwater tetras.

geeez guys, speedy needs sharks with frickin’ lazer beams!

Carmen_Sandiego said:

While Pacific Blue-eyes can survive massive salinity changes (from fresh to double strength salt) they only like water temps down to 20 degrees. Your native rainbowfish, however, can handle down to 10 degrees. Rainbowfish are just as good, if not better, at mosquito larvae prevention so you only need one or two.

Pro tip: Get a few rushes and other plants from a local swamp or even roadside ditch in a pot to put in the pond – the mud/soil will seed the pond with all the best critters and bacteria.

Rainbowfish. Are they native to here in Sydney? My place is right on a creek so it’s important, that if they somehow escape, that they won;t cause a problem. There are Cox’s Gudgeons already in the creek. They are certainly bigger and prettier than the Pacific Blue Eyes.

I already have a clump of native Juncus, which I kept from the old pond. Today I placed it on top of a filled coconut fibre hanging basket insert and placed it into the pond with the plant just above the water level. As these grow at the edges of swamps, finding their own level, I’m hoping that this one will survive long enough to find its own level too.

Thanks for all the info. I will update here again with outcome/s.

Speedy said:

Carmen_Sandiego said:

While Pacific Blue-eyes can survive massive salinity changes (from fresh to double strength salt) they only like water temps down to 20 degrees. Your native rainbowfish, however, can handle down to 10 degrees. Rainbowfish are just as good, if not better, at mosquito larvae prevention so you only need one or two.

Pro tip: Get a few rushes and other plants from a local swamp or even roadside ditch in a pot to put in the pond – the mud/soil will seed the pond with all the best critters and bacteria.

Rainbowfish. Are they native to here in Sydney? My place is right on a creek so it’s important, that if they somehow escape, that they won;t cause a problem. There are Cox’s Gudgeons already in the creek. They are certainly bigger and prettier than the Pacific Blue Eyes.

I already have a clump of native Juncus, which I kept from the old pond. Today I placed it on top of a filled coconut fibre hanging basket insert and placed it into the pond with the plant just above the water level. As these grow at the edges of swamps, finding their own level, I’m hoping that this one will survive long enough to find its own level too.

Thanks for all the info. I will update here again with outcome/s.

All good. Now all I need, is water.

Speedy said:

Carmen_Sandiego said:

While Pacific Blue-eyes can survive massive salinity changes (from fresh to double strength salt) they only like water temps down to 20 degrees. Your native rainbowfish, however, can handle down to 10 degrees. Rainbowfish are just as good, if not better, at mosquito larvae prevention so you only need one or two.

Pro tip: Get a few rushes and other plants from a local swamp or even roadside ditch in a pot to put in the pond – the mud/soil will seed the pond with all the best critters and bacteria.

Rainbowfish. Are they native to here in Sydney? My place is right on a creek so it’s important, that if they somehow escape, that they won;t cause a problem. There are Cox’s Gudgeons already in the creek. They are certainly bigger and prettier than the Pacific Blue Eyes.

I already have a clump of native Juncus, which I kept from the old pond. Today I placed it on top of a filled coconut fibre hanging basket insert and placed it into the pond with the plant just above the water level. As these grow at the edges of swamps, finding their own level, I’m hoping that this one will survive long enough to find its own level too.

Thanks for all the info. I will update here again with outcome/s.

Unsure of which Rainbowfish are native to your area, but whatever you catch from your local creeks should be suitable. (And that also includes exotics – if they are already in your creek system, then you will do no harm if more escape)

Gudgeons, while not as active and entertaining as blue-eyes, are also more than capable of keeping your mosquito problem in check.

Seeding the pond with existing mud/plants is actually a pretty important step – there are uncountable numbers of useful organisms that get transferred that otherwise wouldn’t find their way into the pond and I have actually kept a few small frog ponds mosquito-free without the need for fish by using this method. Fascinating to see the pond teeming with life after only a few days.

Plants are also a very important part of the process. They not only provide hiding places for the fish, but also provide filtration and keep the nutrient levels down. Drop some rushes or other plants into a pot and place them in the pond. You need to remove and prune them once or twice a year or they will outgrow their pots, but every bit of plant you remove is nutrient removed from the pond.

Aye, until I get a very good and thick area of plants my pond was very dull, the goldfish found and ate everything. Now that the centre is a mass of vegetation and areas so thick the goldfish are excluded it has really took off and I even get tadpoles as the egg masses can persist without being eaten. It was very much a critical mass eveny. And the water stays crystal clear now I can even see all the way to the bottom.

AwesomeO said:

Aye, until I get a very good and thick area of plants my pond was very dull, the goldfish found and ate everything. Now that the centre is a mass of vegetation and areas so thick the goldfish are excluded it has really took off and I even get tadpoles as the egg masses can persist without being eaten. It was very much a critical mass eveny. And the water stays crystal clear now I can even see all the way to the bottom.

Good that you are getting pleasing results now.