Fruit flies!

I noticed I had a couple of these in my tank yesterday. I removed any fresh fruit I had in the tank, will they just die off as their life cycle ends? Can they survive in the coconut fiber substrate alone? Is there a safe way to get rid of them? Are they harmful to the crabs in any way?

 

Are they fruit flies, or fungus gnats? Neither one will hurt your crabs, but they will lay eggs in the substrate and the larvae will grow there. Messy and icky more than dangerous.

If you have a gap for air, you can try putting one of these outside your tank, above it:

http://www.biconet.com/traps/stickyTraps.html

It'd have to be somewhere the crabs couldn't touch it, because it's seriously sticky, but it's non-toxic and should attract the insects.

 

They are definetely fruit flies. Can they live in the substrate alone if I have nothing they can eat in there? Yuck! I'm so afraid I will have a ton of them by morning. What do the eggs look like? I have looked for anything suspicious and I dont see anything.

 

I'm going to get some sticky fly tape and run a strip along the top center of the tank where the hermies can't reach.
Whenever I've had these things in the house, they disappeared within a few days as soon as I removed the fruit (usually an over-ripe pumpkin). But I was reading that they need to breed in moist decaying organic matter- which is usually fruit, my question is: is coconut fiber substrate considered "decaying organic matter"? Because if it is I may have a problem getting rid of new off spring. I know it's organic, but is it decaying?

 

Ive had them before in my sand. I was SO lucky when I had them that I only had three crabs, and nobody was down molting, so I bathed everyone, put them into iso, and baked my sand to fry the lil ickies So far I havent had any sort of a problem since.

 

Well this is my new tank, so I am a little upset! I did read that the eggs and larva would only be on the surface of moist decaying matter, When I fist noticed them I had some sliced apple peels in the tank, and one of my guys likes to drag a peice back to his hiding spot with him. SO I am hoping that after removing the fruit will end the cycle. Their life cycle plays out in 10 days so I guess we'll see. If not I'll have thousands of them by then

 

Just an update: Picked up some non-toxic fly tape from Kmart yesterday, and strung it along the top center of the tank lid (of course out of reach from the hermies). So far it is working great. I also had to remove the petgrass that was dying off, because it seemed to be their hang out & I suspect breeding ground. But I stired up the plants and surface a little a few times until all of the buggers where stuck to the tape.. No more flies in the tank that I can see. I'm leaving the tape in for a week just to make sure there are no hatchlings in the future. With any luck I will not have to take any more drastic measures.

 

I looked at the Pet Grass at Petco last weekend...but there were little flying bugs on/in it too. So you probably had the eggs in the grass that hatched in your tank!

 

The things in the pet grass are most likely thrips. They're everywhere. Thrips won't hurt the crabs. They're just little flying midges that feed on plant sap.

 

I'm happy to report I have not seen any more fruit flies. So the tape worked like a charm. I'm keeping a couple of rolls on hand just in case.