Found This..

[archamfr]

no idea what it is. i cant take a photo coz its too small when i zoom it just blurrs. its just a grey sorta egg shape. looks like it got legs, maybe antennas . dont laught at my pic plz lol

 

[black angel]

Could be a fish louse.

Where did you find it in the tank or was it on a fish?

 

[archamfr]

they stay at the bottom, they dont swim. theres about 5 of em

 

[WILDER]

If there disc shaped and have legs it does sound like fish louse.
Check the fish for sores or puncture wounds.

 

[black angel]

They dont swim. Google fish lice and see if its that.

 

[archamfr]

i dotn think it is.. mine dont have like plating.. there just.. smooth.
and 1 or two of my black tetras have like.. sorta blistas on them.. like looks like dead white skin in a ring..

 

[WILDER]

Sounds like you have a parasite that feeding on the fish.
Is it a pink or red sore with a circling of dead skin around the edges.
http/www.fbas.co.uk/Ulcers.html

 

[archamfr]

nothign like and ulcar. anyway 3 of my black tetras are now dead and 1 neon.. howver others look healthy and no mark.. and i have killed all the lil things i can see...

 

[WILDER]

ok, good luck.

 

[Saedcantas]

I'm personally inclined to believe the creatures you gave an artist's impression of were actually Ostracods or Copepods, small harmless crustaceans.

I dont think there is actually much correlation between the disease outbreak your fish are suffering and the unidentified creatures

Could you possibly get a picture of the blisters on the fish themselves for us? As I think that would helo identify the real problem here B)
Lotte***