is this a diatom ?

[mr micro]

hello guys

i found this thing in fish tank ( i suspect its a diatom ) :



is it a diatom , why its so different from the other familiar looking diatoms
i mean.. it looks evil .

[JimT]

Not like any diatom I have ever seen. Looks like half of a hard shell amoeba.

[cuxlander]

Hello Mr. Micro,
it is a testate amoeba, definitely a Centropyxis species most probably C. aculeata.
Cheers,
Hans


See https://arcella.nl/centropyxis-aculeata
(edit this link added)

[mr micro]

thanks guys so much for help , but why haven't i found any normal amoeba in my fish tank
is shelled amoeba more common in fish tanks , or i could find normal amoebas if i looked carefully
and what kinds would i find ?

thanks

[actinophrys]

I know I've seen the occasional little discose amoeba in aquarium debris, somewhat Mayorella- or Korotnevella-like, and in one case lots of the heliozoans Actinophrys among algae films. But whether or not they are more common, testate amoebae are generally more conspicuous. A discose amoeba often looks like just a bit of debris until you watch it for a while; whereas shells like this are not only recognizable, but also endure beyond the living amoeba so can accumulate over time.