SMALL WATER CREATURES! help!

[Shipley18]

ok in my little 5.5 gallon tank i have like a million no exagreation of some very tiny creature it looks just liek a small ball with black spots but you can clearly see that they are alive because they are really far down in the gravel, also they are everywhere? any ideas? also its my sisters tank and she calims she didnt' clean it fo rlike trwo weeks and it was covered in algea a little while ago

 

[lmosness]

I'm not familiar with any of these fish you have but could one of them had babies?

 

[foty89]

I'm not familiar with any of these fish you have but could one of them had babies?

If nothing has been added recently, this may be the case. I don't know anything about these either. This appears to be a salt-water tank, so this topic would best be posted in the salt-water section where you would get a better answer.