what illness is this?

[kurty]

saw that my black dragon betta, the top fin was missing (clamped and spike)

Google and not sure if it's rotting fin or clamp fin.

as clamp fin, the fin will be pulled closer to the body while this is not..

Attachment 46446

already took it out,
added some salt, yellow lotion, black water..

[tureblue82]

maybe a combination of both due to stress?

use yellow powder, quite effective for bettas.

[Guppendler]

Bettas don't do very well in community tank generally.

[kurty]

maybe a combination of both due to stress?

use yellow powder, quite effective for bettas.

Ok, yellow powder and yellow lotion, are they the same??

Bettas don't do very well in community tank generally.

Not really, my 2 other red betta are doing fine except one of them, actually commit sucide.. few weeks back

[hongweijie]

likely fungus infection. use WaterLife protozin.