Water-Strider Things!

[Lockhartia]

I just set up a 26bow about four weeks ago. The live rock's been in for three, cycling. Other than that, the only other inhabitants are some hermits and snails.

Last night I was looking down on the top of the water (it is, atm, an open top tank since there's nothing in it that can jump out) and I noticed these little "bugs" zipping across the surface of the water, much like the water-striders you see in a pond. They were definately on the surface because when I tried to look up through the bottom of the tank I couldn't see them. They were tiny and VERY fast. I tried for about ten minutes to catch one but they were just too small and quick.

I found what looked to be the shell of one, and the closest thing I could compare it too would be a pillbug but with super long antennea that swept backwards as opposed to pointing straight out like most insects.

Does anyone have any clue what this little critter could be? There were probably about four or five of them skitting across the water. With no predators and three weeks of being left alone there is every imaginable pod in that tank, I've just never seen any like this before.

Thanks!

 

[Tennyson]

Yes, I had these too in my tank, but never found out what they were.
How strange, I have a bow tank too.

Anyway, they are little 'water striders' that stride around on the surface, usually near/around the night.
I've observed that they come from the sandbed/rocks/rubble. They were actually little worms that would swim to the surface. When at the surface, they would hatch out of the worm and start moving around with the appearance of water striders...really freaky, if these are the same things.

They're easy to get rid of, pointing a power head towards the surface so there is strong water motion at the surface will get rid of them no problem. And they eventually cycle away as your tank matures.

 

[Lockhartia]

Thanks for the response! I was looking closely at the water's surface when I got home from work, and I definately saw a few casings that were worm-like. I figured they were the molt of whatever critters these things are!

It's just strange, this is my fourth saltwater tank set up, and the first time I've ever seen these! All my tanks have used live sand and have cycled for 4-5weeks with rock before any inhabitants went in. It's crazy what you see when there's nothing there to eat it!

Would love to know what these things are called!

 

[Tennyson]

Same, I asked both of my LFS's, and even brought a couple specimens to show, and they had no idea. And they're too quick and small (and gone for good now) to put a pic up here and ask.

What type of tanks are your other setups? Are any bow tanks also? Just curious if theres some connection

 

[cmpenney]

They are the breeding form form of a worm. Many types of worms do what is called swarm breeding where either part or all of a worm transforms into the free swimming creature you are seeing for the purpose of breeding.

Try Googling for Swarm Breeding Worms.

 

[Lockhartia]

My other tanks are all saltwater, but no other bows. I have a 20ga LPS, 75fowlr and a 55ga sps.....and the bow. I just got the rock a few weeks ago, but it shipped dry and by the time I got to the airport, it was 40degrees and the box had split open and the rock was all over the place. If those worms came in the rock, then they're tough little buggers!

It still amazes me what bizarre little things you can find when you look close enough! Time to google swarm breeding worms! Thanks for the help!