Aquarium filter problem and Taiwan Red Parrot
Thank you all for your helpful suggestions. I implemented most of the suggestions and it seems to be working. I moved the aquarium indoors and the algae seems to have disappeared. I have a light now but as to whether is it a UV light or not, I cannot be sure. I recycled it from some old thing I had in the house.
I might put in some underwater plants to absorb excess nutrients from the water but for the time being, I let the eco-system settle down first.
Notice that the fish seem to be very timid . Perhaps it is just a trait of their species or perhaps I have changed too much water. I had to remove the water as to carry the aquarium with a full load of water from my lawn to the indoors would take a lot of effort. I left about 30% of the water inside a pail.
Notice however two of the fish seem to get along well and seem to be kissing each other all the time. (Not apparent in video). The other fish is always alone and at the opposite end of the other two. It just goes to prove that not only human beings lead a sad and lonely life 
Reduce lighting at initial stage to allow the fish to acclimatise. The tank might be a bit bare and hence, the fish feels insecure and timid.
they seem better now that the water’s chlorine has dssipated..i think. I will think of ways to make the aquarium less bare. thanks
Add a few more red parrots. Put in 9 (a good number) or 18. No oxygen problem. When the fish are not timid, they will respond to your call - tab the glass, and they will come to say hello. Your water looks clear now? It may be cos you changed the water - algae takes more than a week to clear off. Better be sure whether it is UV light or not. Do not look direct into the UV light. The light is harmful to the eyes. That is why it is always covered.
oh it is not covered so it probably is not uv .will look into buying six more red parrots