What is this little creature I found while cleaning my sand?

[Clarkjw2002]

While some mosquitoes will lay eggs in seawater, few survive. The females lay eggs that float on the surface of a pool of water; if the pool dries up, the eggs will desiccate and perish, and thus the association with persisting habitats. In saline wetlands,

This is simply not true. Yes for your average backyard mosquito in the US but many species are adapted to salt water habitats. Anopheles melas along the West African coast comes to mind. In the US, salt marsh mosquitoes are primarily brackish water breeders.

Also, some mosquito eggs, particularly those laid by Aedes spp, can survive years in a desiccated state--look up rift Vally fever transmission ecology. In the US, Aedes aegypti and albopictus can easily last 4-5 months dry. Collecting eggs laid on moist paper towels and then drying is a standard laboratory technique for storing eggs of these species for future propagation.

 

[Clarkjw2002]

However it happened it was mosquito larvae--not something that came from the previous tank in the sand. Mosquitoes can use surprisingly little water as a habitat--think those ridges in French drain pipes (a commonly overlooked backyard habitat) or a hoof print in the soil.

Could have spilled in from the lid or condensation in the can created enough water for them to grow (that pic was a 4th instar getting close to pupation). Based on stage of the larva, the eggs were laid probably 5-8 days before the pic was taken. Or the eggs were already on the side of the can. Look at any outdoor container just above the water line. Look close and you'll probably find little black eggs this time of year. Those are Aedes spp. eggs and it is how they lay (just ABOVE the water line). Culex lay eggs on the water surface as rafts and Anopheles as single eggs on the water surface.

Not that any of this matters for your tank. Either way, nothing to worry about in terms of using for your tank even if a few got through.

 

[corJoe]

movement reminds me of mosquito larvae

I saw the video, instantly knew what it was, and thought, "kill it with fire". I hate mosquitos.

 

[Boaz1021]

I saw the video, instantly knew what it was, and thought, "kill it with fire". I hate mosquitos.

Oh, I HATE mosquitoes also, but normally the small ones I see swimming are much smaller than that. I have 2 Spartan Mosquito defense traps, a few bug zappers and even have Orkin spraying for those SOB's. I wish MS would take after FL and release genetically modified mosquitoes that can't reproduce in order to combat their populations.