Fungus Gnat Control

[Fireball]

Fireball, my Chinese Firebely newt, lives in a divided 5.5 gallon tank, about 2/3 water and 1/3 soil separated by plexiglass that is silicon-ed in place. I checked that it was watertight, but I didn't account for capillary action once I had water, soil, corkbark and moss all set up- the corkbark and moss wicked the water right into the soil, and for months now, the soil has been mostly saturated. And this has led to fungus gnats.

I can let my houseplants dry a little more, but this viv is harder. My last resort option is changing out the soil for new, but I'd like to address everything else first. Has anyone used Bacillus thuringiensis (or Bt- in products like Gnatrol) with aquatic amphibians? It's supposedly organic, and fatal to the gnat larvae. Also, I have heard that a layer of sand over the top of the soil keeps the gnats from reaching the soil where they lay their eggs- could it really be as simple as this? If I use the layer of sand trick, the sand will surely become saturated too- will the gnats still be deterred?

I am also trying (with little success) vinegar traps, rum traps, and manually crushing any I can get my hands on.

Any advice folks have will be appreciated!

 

[Jennewt]

Even without the total saturation you had, I think you would have gotten fungus gnats anyway. Any slightly moist soil is enough to get them going. In my experience, nothing deters fungus gnats except a total lack of soil or a total barrier. I keep a piece of cloth under the lid of all my terrestrial setups, and this keeps the gnats out (and the fruit flies in!). However, it would take some ingenuity to make this look non-ugly, and you'd have to completely clean out the tank and start over to get rid of the existing gnats.

 

[stevethegator34]

You could try planting a few carnivorous plants, such as tropical varieties of pinguicula or pygmy drosera species. these plants love the fairly nutrient poor, constantly moist soil typically found inside of a vivarium, and their flypaper-like trapping mechanisms are the most suited for trapping fungus gnats. (don't worry, they're harmless to larger animals such as amphibians) However, these plants are very sensitive to soil chemistry and thus cannot be planted in traditional soil. While peat moss is usually the preferred medium of choice, some have said on this forum that it may cause problems for the tank inhabitants. Instead, I would recommend coco fiber, which has been used successfully amongst carnivorous plant growers and amphibian keepers. For more information on growing carnivorous plants in vivariums with amphibians (specifically dart frogs), you can visit www.blackjungle.com. Plants may be obtained from various internet retail sites.

 

[stevethegator34]

*correction* coco fiber only works with plants in the genus nepenthes, not pinguicula or drosera. However, if your current substrate supports moss, it may also be suitable for CP's.

 

[peterj]

The CPs won't keep up with a gnat outbreak and I'm not sure your newt would like the amount of light they need. While they are annoying, they're pretty harmless. You could always try putting a trap in the room, red wine in a jar with a funnel in the jar mouth catches them by the dozen.

 

[Mark]

I’m with Jen on this one. Unless you have a fly proof lid they are very difficult to prevent. My tips for controlling them would be:

• Refresh the substrate with sterilized soil/bark/coco-fibre. If you can’t buy pre-sterilized put it in the microwave until it’s piping hot.
• Buy some sticky fly paper and hang it near the tank – if you have a good infestation you’ll be surprised at how many will get stuck to it.
• Make the lid more fly proof.
• Routinely open the lid to let adult flies out and where possible open windows to allow the flies to leave the house completely.