Amphipod? Shrimp? Idk…

[AwakenedReefer]

So these little critters are in my tank and I want to say they are amphipods but they behave and look a bit differently than I remember and they have 2 white dots on their backs. I can’t seem to find pictures of them anywhere. If someone can ID these creatures I would be grateful.

They spend most all their time in the little holes in the rock. Now and again they will come out real quick grab a piece of sand and back into the hole. Sometimes when they cross paths they fight. They have daggers folded under and they use them. Quit entertaining.

 

[vetteguy53081]

Any still pics under white lighting? Can’t open video on my phone.
Most shrimp like occupants end up being amphipod which can get large
Time to time, live mysis shrimp show up also

 

[AwakenedReefer]

Here are some stills. They are quick just in and out. In the first and second pics are good side profiles. The third pic you can see the back markings better.

I will get some white lighting pics when they come out and play again.

 

[WheatToast]

So these little critters are in my tank and I want to say they are amphipods but they behave and look a bit differently than I remember and they have 2 white dots on their backs. I can’t seem to find pictures of them anywhere. If someone can ID these creatures I would be grateful.

Amphipods. These can be highly variable; I have seen images of captive, spotted amphipods, but I cannot recall where. Spots or no spots, these should be beneficial scavengers.
With multiple spots:

They have daggers folded under and they use them.

Some amphipods are armed with very prominent claws which are somewhat common in our systems:

Most shrimp like occupants end up being amphipod which can get large

I haven't personally seen this in my tanks, but they are indeed much larger than the more common copepods. Deep-sea amphipods take this to the next level:

 

[vetteguy53081]

Here are some stills. They are quick just in and out. In the first and second pics are good side profiles. The third pic you can see the back markings better.

I will get some white lighting pics when they come out and play again.

View attachment 2847074 View attachment 2847075 View attachment 2847076

This may be a gammarid which is an omnivore and shrimp like in appearance

 

[WheatToast]

This may be a gammarid which is an omnivore and shrimp like in appearance

+1. Gammaridae is a family of amphipods.

 

[AwakenedReefer]

The Gammaridea looks pretty close. They have not been a problem and are interesting to observe.

They pick a small pore in the rock and back into it leaving their antenna out. Every now and again you will just kinda see the two white dots come out grab a piece of sand and they back up back into the hole fairly fast. When they cross paths or another critter comes to close it’s knives out. They fight for a couple seconds it ends and they move on. They seem pretty territorial and I think mostly active during the day. I have not looked for them specifically at night.

Interesting thing is I have not noticed any of the “familiar looking” amphipods in my tank. Just seems this species for amphipods.