Newbie Needs Help With Plant

[regimail]

I have kept a tropical tank for couple of years now. Till now used to keep fake plastic plant in my tank. After seeing this forum I was tempted to get some real plant. I have not previous experience of keeping real plant in the tank. I went to LFS and bought following 2 plants.
The first one is amazon sword plant I think. (I have angels in my tank). Is this correct and does anyone know how big they can get?

I don’t which plant is this.

In 2 days I have noticed these plants have started breaking up and the stems have started floating on surface. When I bought these I noticed they were just plant cuts bunched together without any roots. Is this normal?
Also I have noticed they are losing colour and becoming brown near the bottom where they are bunched. This is the place where each stem is breaking off and floating on the surface.
I have recollected them and bunched together and planted them again. The question is will these plants survive at all. Is there anything I am doing wrong?
I don’t have any CO2 system or any special lights. I just want to try out first and see if I can keep live plants in my tank.
Aquarium has 2 fluorescent tubes which I heave on for about 8 hrs a day. Is this enough?

Any help is appreciated.

 

[aaronnorth]

first looks like amazon sword, and they get massive!

2nd is elodea densa.

stem plants may not have roots when you buy them, but they will estableish some once they get going, it doesnt matter though as they get most of their nutrients through the water column.

has it got a metal weight on? if so take this off. And also, plant 2 stems a few cm apart from each other so the light can get to the bottom.

 

[regimail]

Thanks for your response.

I bought 3 bunches, each bunch has about 10 stems in them. They are wrapped in a sponge with a metal piece holding the bunch in place. I will remove the metal piece and plant 2/3 stems together at some distance.

How do you make it stay in the gravel without the metal piece. Will it stay in the gravel at the bottom if I put enough gravel around it or after some time it will come out of gravel and start floating. Are there any tricks I can use to keep the plants in gravel. For e.g. tie them with thread to a tiny thread of tank decoration ...

I have checked the lights in the aquarium. I two have Triton 30W. I will increase the light time to 12hrs and see it makes any difference.

Someone told me that you get different varities of amazon sword plant and some stay small. I am bit worried about that. I have a tall tank and would like it to grow tall till the surface.

 

[aaronnorth]

it will stay in on its own, eventually producing roots,