fishes all died except for one, why?

[ferocios31]

I had about 5 fish, all hardy in my 25g tank about 3 months ago, along with one cleaner shrimp. It was getting rather hot in the area I live, I was out of town, and the majority of my fish have died. these were the fish i had:
 
gold head sleeper goby
spotted cardinal
bengai cardinal
ocellaris clown
chromis
cleaner shrimp
 
the water is fine every time i take it to my lfs to test...
 
when i came back from my 1 week trip, only the cleaner shrimp and spotted cardinal were alive. i had someone feeding every other day, so the only thing i could think of was a build up of nitrates or the change in temperature. at that point, i didnt have a chiller and my "built in" filtration system of just some bio balls in sponges sucked, so the temperature fluctuated up to 84 to 86 degrees.
 
i just dont understand how only the spotted cardinal survived with the cleaner shrimp??? are spotted cardinals hardier then the other fish?
can they survive in water that isnt as clean?
 
someone told me that oxygen and ph levels are key in keeping fish alive, besides the obvious elimination of nitrates. i have the proper amount of live sand and rock.
 
ive now gotten a 1/15th arctica chiller to regulate temp and a fluval canister 205 to regulate the cleanliness of water. i also bought a small skimmer to help additionally clean the water.
 
i tried putting a chromis in the other day to see if he would survive. its now been 2 months with the cardinal and shrimp in the tank alone. the cardinal is chasing the chromis around, although the cardinal should be a peaceful fish. the chromis just died today in the morning, so i am frustrated because the cardinal has lived this long, yet new fish i am acclimating are dieing off. anyone have any suggestions? Thanks in advance!

 

[flower]

 
 
Sorry to hear of all the trouble. when a fish is new it is stressed, and if it gets chased around it adds to the problem. A skimmer was a very good choice. 3 months is just about the time a skimmer is needed. It pulls out stuff you can't even test for.

You really should get your own test kits, LFS take shortcuts on tests and are inaccurate as the result. For example there was one test where you add a drop and shake the test tube with each added drop..Years ago I had the LFS test my water and the guy was adding 5 drops at a time. I don't remember the test now, nor why I needed them to do it..but the fact the guy messed up the test stuck in my head.

Vacation is scary for all of us...it never seems to go well for someone else to care for the tank.

 

[nycbob]

without listing ur water parameters, there isnt much we can tell you. get a test kit, and test for ammonia, nitrite and nitrate. how much lr do u hv in the 25 gallon?