Tropical Freshwater Tank 2 fish have died this week!

Question
I am baby sitting my boyfriend's 22 gallon fresh water tank for 5
weeks while he is in Europe. The tank is home to about 12
community fish, that all get along very well. Many of the fish he
has had for a few years and they all seem pretty healthy. Before
my boyfriend left we bought two clown loaches. After we had
them in the tank for a few hours we noticed that one seemed to
be pretty skinny. The other was fine. So for about two weeks
they were all doing well. On Friday the skinny one past and I
don't know why. I feel as though there was something
genetically wrong with it because it would eat and act like the
other fish, it was just thin. Then two days later one of the older
(about 2 years) rosie barbs lost its color and its stomache bulged
to huge proportions. Then it start swimming side ways and
upside down. after a few hours that one died. Today
(Wednesday) one of the tiger barbs (about 2 years as well) is
starting to show the same symptons as the rosie barb. I'm really
worried and I would like to know if there are any connections to
the loach death. What can I do? Do you think this could be a
disease that is spreading?

Answer
Hi Lauren,
Thank you for your letter. My outside observer's opinion is that you are over feeding. If the water is cloudy or viscous, just stop feeding for a few days. Then resume with one flake or pellet per square inch of fish.
Buy a bottle of Cycle, friendly bacteria. It's expensive, but it will help save the fish. Follow the directions on the bottle and keep it in the refrigerator between use. If you think you can manage it, follow the emergency care instructions at the bottom of the page:
http://steamboats.com/aquarium.html
Be sure to keep the water temperature steady as you change the water.
If it seems like too much for you, just quit feeding and then feed very moderately until b'friend returns.
Yes, disease will spread if you continue to pollute the water with too much food. If you stop over feeding, change out some of the water and add the recommended dose of Cycle, things could stabalize.
Yikes! Another thing: don't get mad at yourself. It's a difficult hobby for anyone.
Write back if you want to discuss further.
Nori