mollys dying

Question
QUESTION: in the last 4 weeks 3 of our mollys have died with no obvious illness. another one is now sinking then struggling back to the surface. all our other fish seem perfectly healthy (1 siamese fighter, rainbow sharks and swordtails). we clean tank regulary, adding appropriate salt and water cleanser. i am stumped.

ANSWER: Hi Kath,
 Is it possible that the swordtails or betta are attacking the mollies? That would be my first guess.

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>


---------- FOLLOW-UP ----------

QUESTION: i have seen no aggressive behaivour towards the molly's. i am now treating my siamese fighter for fin rot. i know the swordtails have been nipping her because of her trailing fins. i was told that swordtails are placid and will live with most fish.

Answer
Hi Kath,
  Fin rot is very seldom an actual problem. In fact, I have seen very, very few cases of real fin rot in thirty years of keeping fish.  "Fin rot" is usually the result of another fish biting the fins of a fish such that the fin looks tattered and starts disintegrating.  

  Whoever told you that swordtails are placid and will live with most fish doesn't know what they are talking about.  Male swordtails are  territorial and can be aggressive.

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>