fish behavior..are they sick?

Question
QUESTION: About 2 weeks ago my daughter won a goldfish at a fair.  I set up a 10 gallon aquarium with filter and bubbler.  The fish was doing fine.  Eight days ago we added 3 other goldfish to the tank.  A lionhead and 2 fancy goldfish.  They seemed to be fine at first.  After 3 days the lionhead died.  Since then the other three have seemed fine until yesterday when they (all 3) started spending a lot of time at the bottom of the tank.  They also don't seem to be moving their fins a lot.  If we go over to the tank they start swimming around again...until we walk away, then they're back to the bottom of the tank.  It's been warm here and I've been struggling to keep the tank under 75 degrees by adding ice several times a day.  In addition I've made 15-25% water changes twice a week.
Is this a behavior thing or is there something wrong with them?
Oh, and I had the water checked after the lionhead died and they said everything was good with the water.
I'd appreciate any help.
Thanks!

ANSWER: Also if you get a bigger tank the temp. will not be so hot that should help the heat problem. Are you putting water dechloriantor in the water after you make the water change? If not you need to start because their are chemicals in tap water that are harmful to fish. Are you checking your water for P.H., nitrite, nitrate, hardness, alkalinity, and ammonia because if you are not you need to get a test kit because your fish might be stressed from something being to high or too low. You should feed your fish twice a day and for a food i would reccomend "Omega One" that is a good brand and they have food for goldfish that has high protein and vitamins for a heathy and long living fish.

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

QUESTION: Thank you, thank you, thank you for all your help!!
I tested the water and the Ammonia was high and have since treated that.  In addtion they have Ick and I've treated that as well.  They are MUCH happier little fish and I think I have control of the situation.
I must say, in a couple of weeks I've gotten attached to the little things!
Thanks so much!!


Answer
Well it sounds like you are having some good luck with the fish i hope everything else goes well. don't forget to do weekly water changes of about 25% percent and make sure you vaccum the gravel bed so all the food,waste, ect. comes out of their.

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