Sevrum with white fins

Question
Hello,
 We have a 30 gal Marineland system that came with filter and heater etc.  We followed all instructions for setting up, running a new tank, waited to add any fish until water was tested and was just right.  So, I think we are good there.  We do our water changes weekly and have taken water samples each week to make sure we maintain a healthy tank.  We bought 2 fire mouths and a sevrum, all of who were tiny.  The fire mouths were mean.  One more so than the other after a month or so.  We had added a large angel and the fire mouths attacked her.  Once she was gone, they seemed to go to work on the Sevrum.   In order to save the sevrum, we gave the fire mouths to someone with several large tanks.  So, we now have peace restored in our tank and have slowly added a couple more angels and 2 small rams.  However, the sevrum continues to hide most of the time, and has cottony patches on both of her side fins.  Can this be from injuries?  From hiding in the tree stump (artificial) or is it fungus?  He does come out to eat and they all seem to leave each other alone when he is out.  I've read about the fungus, and it looks like white cotton, but he was injured.  Should  treat the whole tank?  Thank you so much!

Answer
Hi Charlene,

What often happens, is a fish will get injured, and a secondary infection will come along and harm the fins.  This, I believe, is what's happening.

He probably needs immediate treatment.

Please set up a 5 gallon tank to treat sick fish in.  Everyone who starts a fish tank should always keep a hospital tank close by.  This prevents necessity of treating an entire aquarium for one sick fish, when treatments often kill the beneficial bacterial cycle.

Set the tank up with 2 teaspoons of marine salt in it per gallon, dissolved.  That's 10 teaspoons of salt for the 5 gallon tank.  Add a small heater.  Heat to 80F.  Add a small filter.  This will probably end up costing about $50, but once done, it's over with and you will always have it when you need to set it up to treat someone.  Believe me, what sounds excessive right now is one of the best moves you can make as a responsible fish owner.  It will save many tank breakdowns in the future if you buy fish from petstores.

Stick the sick fish in there til the fins clear up a little.  My estimate is a 5 day treatment in that water and then return him home.  The fins should be cured of any fungal activity.

Meantime, drain the hospital tank and save it for when you bring new fish home from the pet store.  New fish go into that tank for 2 weeks before entering your other systems, forever.  This will prevent you from getting Ich in the main tank and other maladies and parasites, often carried in with petstore water.

To transfer a petstore fish, get out 2 bowls.  Put the fish and petstore water in one bowl after floating it in the hospital aquarium awhile, allowing it to acclimate to the temp of the main tank.

Fill the 2nd bowl with hospital tank water.  Scoop out the fish from the first bowl into the second and then add 2 drops of anti-ich medication and allow the fish to sit in that water for 15 minutes.  Cover it so he doesn't jump out.  When he's done soaking in anti-ich medication, you can then take your net you just used, wash it thoroughly in hot water and cool it.  Then you can take that and remove that fish and add him to the hospital tank where he lives for two weeks in hopes that if he did arrive with a disease, not only did you kill that disease right off the bat, but he did not carry it to the main tank!

:)

Happy fish-keeping.

Renee