oscars white spots

Question
QUESTION: i have community tank of 150 ltr. in this i have 1 red tiger oscar for a month. its having white spots on fins. i added common salt, cleaned tank, added anti fungal and anti-bacterial liquids. but its still there.oscar is active eats normally. pl tell me what should i do. thanks. arvind
ANSWER: Arvind-
Believe it or not, this is actually a natural occurrence.  Sometimes, during development, Oscars occasionally, get discoloration on their fins.  My tiger Oscar has a white spot on his dorsal fins.  They're perfectly fine.  As long as he's eating fine and is active, I wouldn't be worried at all.  You're going to be fine.  Good luck!

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QUESTION: thanks for quick response. the white spot is on pectoral fins. sometimes blood parrot which is of same size fights with it. one one tiger shark has been eaten by other fishes of tank, oscar,parrot, red belly paku. i cold not see who did it. should i keep other tiger shark in tank or not.
ANSWER: Tiger shark isn't aggressive enough to stay in that tank.  Pacu, Oscar and a Blood parrot.  You really should remove the tiger shark.  

On a side note, a 150 liter tank really won't hold an Oscar to full term.  eventually you will need to decide which of your monster fish you want to keep.  The Pacu will get huge, so will the Oscar, and the Blood Parrot just gets in the way.  For now, though, you should be ok.  Good luck

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QUESTION: upto what size my tank can hold these fishes.pl tell me about how to make tank clean. i have one power filter and one filter with sponge.should  i add iodised salt or raw salt. for how much time light should be on. at any time should i change 100% of water i should follow ony 20% water change every week.

Answer
To keep all those fish, you going to need a 150 GALLON tank, which is about a 750 liter tank.  DO NOT add iodinized salt!  It will kill your fish.  Aquarium salt only.  You'd need a bigger filter for sure.  Never change 100% of the water.  Theres nothing wrong with your tank.  The spots on your Oscar are natural.  Keep changing the water 20% a week