Select fish dieing with water change??

[Alison.P]

Tank 120L
Fish:
4 clown loaches
5 tetras
1 bumble bee catfish
1 mossy barb
3 albino corys
1 electric yellow cichlid
1 bristle nose catfish

(i'm a new member of this site!!)

A few months ago i did a water change (probably about 20-30%), at that time i had 2 silver sharks and eveything above except the cory and the bristle nose. upon completion of my cleaning regime i noticed that one of the sharks wasnt coping at all with the slight change, about 10 minutes later it died - i actually watched it (very sad really but interesting). the next morning the other shark was dead.
This happed to me last time i had sharks (3 of them), about 9 months prior to this, they all died within 24hrs of the change. I try to do regular water changes at lease every 2 weeks if not every week.

i did a pretty thorougher clean of my tank today with a 30% water change - a bought another cichlid early this week, it seemed healthy until the clean, i just came up to find it on the bottom dead!!!!

None of the other fish have been affected!!!!!!

why is this happening???

Any helpers??

 

[DragonFish71]

Make sure when you're refilling that the water is close to the same temp as the tank water and that you are treating (with dechlor) for the size of the tank, not what you are replacing.

 

[mfdrookie516]

is this a 120 gallon long tank or is it a 120 litre tank?

 

[Alison.P]

120 Litres, what is MTS?

Dragonfish: yeah i think that may have been my problem, iv noticed that my decholrinator is out of date by more than a year now.... so im waiting on some prime in the mail!

 

[mfdrookie516]

mts can mean one of two things, maybe more... in my signature, im referring to "multiple tank syndrome"... its just a joking way of saying ive got too many tanks and cant stop getting more...