Black bug found in nano shrimp tank hlp???

[Tammy080]

So I found this little guy in my shrimp tank. At first I thought a bug had just fallen in and sunk to the bottom,but then he starts swimming around. He could move very quickly in the water and had no trouble swimming freely or walking along the bottom. I finally netted him and put him in a container. I can't find this online and I just want to know if there are any more to worry about. It's a good half inch long so I'm worried if there's more they could eat my smaller shrimp.
Anyone have advice or know what it is?

 

[myswtsins]

Hard to say for sure from your photo but it is probably some sort of nymph/larvae. Look at the dragonfly nymph of THIS page. If that is what it is they are dangerous to small fish and inverts. Good news is that with some observation they should be easy to discover and remove IF there are anymore.

 

[Kaliska]

I got damselfly nymphs in a tank recently. If you don't have fish to eat them when small they can reach dangerous sizes and become carnivorous. Many winged insects have a water nymph stage. Usually they have a longer abdomen than your pic but the long, tapering, striped legs are a common feature of nymphs.

 

[Tifftastic]

It definitely looks like a dragon fly nymph to me. I assisted with a project where the group used them to see if they would control invasive fish on the refuge. They will eat fish quite a bit larger than themselves and from experience, if you get bit it HURTS

 

[henningc]

It is a dragon fly nymph and it will eat fish eggs, shrimp and fish if allowed to grow. I have had a few in my time and just don't fling it in a cichlid tank and think it is over. Some must taste nasty as my jacks and fire mouths wouldn't touch them. You can always raise it in a gallon jar giving it pond snails to feed on. Cool project if you want to mess with it.