black streaks on fins

hi, i have 2 small cichlids in a 55 gallon tank, yesterday i did a 50% water change and now one of them has black streaks on its fins. i read on a website that this is a kind of ick, do i need to treat the water?
the fish doesnt seem sick. the ph is fine.

Comments

black streaks

no, black can appear for numerous reasons, read up "black spots" on this site, its more likely to be that they are a little stressed from the water change(was it the first one?)did you dechlorinate the new water and match the temp to the tank water? funnyly enough, the general treatment is regular water changes, maybe just a 20-30%,they develop black spots and streaks from poor water quality, change in temp, change of environment, different food, spawning activity,unsuitable tank mates etc etc,if it persists after two weeks of water changes (every 3 days or so) post back,let us know anyhow