My poor little fish is swimming erratically.?

[Bryan]

I have a 12 gallon aquarium i have had for 5 months now. 2 of my fish died last week so i did my usually water change today. i kept a little water in the bottom so the good bacteria in it would help the aquarium. i used 9 gallons of pH balanced bottle water. i added 1/2 a dose of ick remover since all of my fish were kinda acting funny, everything seems to good now except for my yellow (molly?). (it yellow with black dots on it tail). i bought him from Petco probably 3 moths ago. he had a mate but she died last week. Right now i have 1 chinese algae eater 1 white molly (dominant) 1 red platy and the yellow guy. i lost 2 black mollies and the yellow female last week. the white, red and CAE fish are fine. the yellow one is swimming erratic then is ok then is swimming erratic. what should i do. have i already messed up? i would like to keep him in the aquarium since it is treated. He seems to be eating ok. he swims from the top to the bottom ok. help plz. sorry i posted on Christmas Eve.

[SuperDog246]

Look, I don't know what choo be talkin bout Willis, but sounds like that fishie is talking about going to be with Jesus tonight.

[Mokey41]

Not sure what is wrong with your fish now but don't do such huge water changes. 10 to 25% is the most you should take out on a regular change. Taking too much can really throw off the balance of the bacteria. Your tank was on the border of being overstocked before so maybe your ammonia levels were getting too high for them. Try not to exceed about 1" of fish per gallon.

[?Dingo Girl? (Thumbs up!)]

Maybe it's discombobulated.

It's sad I lost a fish. Jason Reitman made a short film about savaing a fish. GULP
http://us.imdb.com/title/tt0270982/ it's on youtube but don't watch it if the subject matter is a little touchy right now.