Pleco Fish Dying

I am a new fish tank owner. I got the tank for christmas and have had it running since January 11th. I let the tank cycle for about 9 days before adding an electric yellow lab. A week later I got the water checked again and added a red zebra and a pleco. The pleco didn't swim around much and after about a week I noticed he was on his way out. He wouldn't eat, wouldn't swim, nothing. About a week after he died (2 weeks ago) I got another pleco. When I first put him in the tank he went nuts I don't think there was an inch of the tank he didn't cover. Last night I noticed he wasn't himself he was just resting on the gravel. This morning he was swimming up to the tank, trying to attach and just floating to the bottom and laying on his back. He died about 3 hours ago and I don't know what I am doing wrong. I fed him algae wafers every day and my tank levels seem fine. He didn't have any white spots on his body but I noticed once I pulled him out he had a little bit of fin rot on one tiny fin.

Nitrate- 0-.5
Hardness- 75 soft
Chlorine- 0-.5
Alkalinity- 80
PH- 7.2

What am I doing wrong?
http/www.petsmart.com/product/index.jsp?productId=3954163&lmdn=Pet+Type

Chlorine should be zero.

Do you use something like stress coat or prime?

Do you keep the light on for 8-12 hours a day?

I feed mine one algae wafer every other day.

Also, inspecting my yellow lab he looks much paler than usual and has 3 tiny white spots. He seems to be acting normal. Could it be ick?

SG_Dude said:

Chlorine should be zero.

Do you use something like stress coat or prime?

Do you keep the light on for 8-12 hours a day?

I feed mine one algae wafer every other day.

Click to expand...

The chlorine is very hard to tell on the test strip. 0 is white and .5 is off-white.
I use both when i change the water.
The light is on from 8am to about 9pm and I gave him a wafer every night.

If you can get yourself a liquid test kit, it'll be easier to accurately read the levels in your tank.
also, it sounds like you're in a fish-in cycle, so you might want to read up on that here.

Your tank is not cycled which means you do not have enough bacteria living in your filter to make the water non toxic for your fish and they are being poisoned. It takes between 6-8 weeks to fully cycle a tank and you are going to have to change between 50 and 30% of the water daily until its cycled! You need to read up quickly on how to cycle a tank with fish in it on the link MISLISA has given you above before more fish die.