Unidentified Creepy Critters - Uccs - In My Tanks? Help

  1. Cold&warm

    Cold&warm Valued Member Member

    Hello to everyone!

    In one of my basins I occasionally dump a little water from filters. The bulk of the basin's contents is old tap water.
    A moment ago I discovered these critters (I posted here because I am pretty sure they have no vertebrae): IMG_4345.JPG IMG_4347.JPG
    Could anyone tell me what they are? They move slowly. The "body" is between abt. 0.4" and 0.8" long and that strange threadlike appendix is much longer.

    It is not very likely I will feed them to my fish, not even to my voracious (dwarf red) Blue Gularisses (aka Fundulopanchax sjoestedti, one of the 2 males male to be seen in the avatar). Would these animals eat my fish? They kind of make me worry..

    Thanks in advance for any reaction!
  2. midna

    midna Well Known Member Member

    hmm, these are kind of terrifying :) no clue as to what they may be. aliens?
  3. Keystone

    Keystone Well Known Member Member

    They look like drone fly larvae to me - sometimes called rat tailed maggots. The long "tail" is actually the breathing siphon.
  4. OP

    Cold&warm Valued Member Member

    Keystone, thank you very much!

    I looked them up in wiki: Eristalis tenax - Wikipedia .
    When I saw the pictures in the article I recognized the mysterious "guests", half fly - half bee, that since a couple of years turn up in spring in my washroom:
    There are only a few of them, I guess 5 or so. They do not sting and sit on the wall. Rarely do they fly. After about a week, when they have mated they start to wither away, getting thinner and thinner. And a little later they're gone.. only to appear again the following year.
    Thanks to your answer now I know that I must get rid of them ...