Originally Posted by Pilik-Palak

IMO,
uf fish hv a very weak bone-rack(normall happen fequently on our local goldfish due to breeding in mature parent stock).
As ur case as i look close ,
1)it a genetics as the fish grow older ,the bone cannot support the longing fins and cause the fins to bend.
2)could due to torn of the bone rack as i seen ur fish hv very thin bone structure.
3)do u used power head that hv 2 in 1 funtion?.one goes to the top chamber,another shoot at the front with bubble circling the water.
4)over crowed could be another reason.

i don't think medication could help as i seen no bacteria of fungus infection.
hope that help.cheers