so i came home from work today and notice 2 of my fish have some chunks missing out of their fins, i dont know if its fin rot or just them being spaztic and running into the rocks and doing this to themselves. if it is fin rot what should i do to fix it and if not what it going on? only 2 of my fish are that way and they are the same fish but they have scratches on their heads too. im still pretty new to this so any help will be thankfull.
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What kind of fish is it? (certain fish cannot handle salt)

First thing I would do is give them a salt dip.

I do this when I notice pretty ripped up fins from fighting in my African tank, signs of ich and new fish. It stimulates their slime coat to help them heal faster, also helps in getting rid of any external parasites.

To give a salt dip, fill a bowl or small bucket with tank water, add about 4 teaspoons of aquarium salt per gallon of water. Mix it up very good. Then net the fish and put it in the bowl for about 2-5 minutes. If they thrash around add more water. Mine usually stay pretty still. I just let them stay in the net. Then put them back in the tank when the time is up. You can do this twice a day. It helps them heal and is also good for getting rid of parasites too.

I do this for all new fish before adding them and when there is signs of ich. It helps them to heal.

Here is a couple good article's about the salt baths:
http://www.algone.com/fish_dips.php
http://freshaquarium.about.com/cs/treat ... nfresh.htm

well they are the silver tip sharks, and well yeah i have tetras but they couldnt get these i dont believe, so yeah the one fin looks ripped but they only stay still enough if i sneak up.
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