They only come out at night!!! What are they???

[mwita06]

At night when there is only enough light for me to see, these little critters come out and zip all around the tank. They are about the size of a tiny grain of rice. Their bodies appear to be clear, and you can see their spine. They seem to glide very quickly along the rocks and the sand. Almost like little fleas zipping all around the tank.

What are they??? Will they become problematic??? Or are they beneficial??? (I assume the later)

My tank is a 30 gal. 30 pounds of live rock, live sand, 3 fish, 4 crabs, 3 anemones, 2 sand sifting starfish, 4 turbo snails, and maidens hair. 2 penguin eclipse filters, and 130 watt compact. I use "All in One," and replenisher cubes.

[clownin around]

These are copepods and or amphipods. They are not likely to be any sort of problem and are cocidered a sign of a healthy maturing tank! There are many types and varities of these creatures. HTH

[ddcboys]

I agree with Clownin

[two11devan]

I think the two sand sifting star fish will become a problem with your sand bed. I was looking for sand sifters for my 30 gal and was told that most sifters such as stars and horshoe crabs will eventually eat everthing in your sand bed and will eventually destroy it.... Just my 2 cents

[NaH2O]

>>>What is this critter?<<<

>>>Odd Critters<<<This has some good pics in it, too.

Hope these are a start. I also agree with two11devan, the sand sifters will decimate your sandbed, and you need the good critters to take care of the detritus.

[Bang Guy]

I disagree with Clowning. I believe they are Mysid Shrimp.