problem of 2 fish types

Question
Hi, I prepared my 60 liter tank for a month, I have 2 catfishes, 3 swordtails, yesterday I bought 2 new angel fishes it seems that 2 female sword tails are biting and chasing these new angel fishes, I don't know what to do can you please help me?

Answer
Hello
You must not mix swordtails, guppies or Mollies with Angel Fish.  The beautiful long fins on the Angel Fish is an attraction to these fish.  They will nip at the fins of the Angel Fish, and eventually your Angel Fish will get sick as they are stressed.  You must bring the swordfish back to the pet store, and ask for a credit.  Little catfish are cute, and won't bother your Angel Fish.  You have no other choice, unless you want to keep your swordfish, then you must bring back the Angel Fish.  A fifteen gallon tank is actually too small for two Angel Fish.  Angel fish do get big, and they would need a 35 gallon tank.  If you decide to keep your Angel Fish, please do not add anymore fish.  Keep the catfish, with the Angel Fish, but one day later on you will have to get a bigger tank.  Water temperature for Angel Fish is 80 degrees, and the PH should be 6.5 to 7.0  Angel Fish do not live in Alkaline waters.  Make your water changes every week.  Make sure you have no ammonia in your water.  Ammonia test kits may be bought at your pet store, and they are very handy to have.
A little more on Angel Fish...They should have a good diet.  A good flake which as vitamins, and frozen brine shrimp, bloodworms, daphina, frozen or dry.  The more variation the better.  When fish are not stressed, are in clean water, and have good food, they seldom get sick.  It is better to pay a little more for good food, that to have to pay to cure them.  Sometimes the medication can be very costly.  I just thought I would add this to your question.
Hope this helps
Lynda