I agree that your yellow lab will give your tetras a beating. My friend had one in her 20g community and she had to put it in its own 10g after about 2 months. The only thing that can survive being in the tank with it so far is my syno eupterus. Her yellow lab killed a red tailed shark, 3 platys, 1 molly before she finally listened to me and moved it to its own tank.
As far as the algae, what type is it? If this is a new setup I would guess diatoms and it will go away eventually.
On a more positive note, I love the real plants, looks like they are going to grow to the top at this rate!
Keep up the good work!