[bettababy]

Blue is right, on both counts. The shark doesn't belong in a 10 gallon tank, and won't last there for long, and live plants will help your tank tremendously, though I won't say that fake ones are useless. I coach people on how to have both in a tank, it depends on the setup.
The rubber pleco will outgrow that tank as well, but not as quickly. Eventually that rubber pleco will need a minimum of 55 gallons to keep it healthy and well fed. They are known to eat a lot, and they need room to move around decent. They also get to about 5 inches in length, and are sensitive to water quality. This is not the kind of fish to put into a new tank. It will need to be fed regularly during cycling because there is no natural food supply yet present. Live plants will help to feed the pleco, especially elodia (anacharis), which is one of its favorites. So, for more than waste reasons, I would suggest adding live plants to your tank. That may be what helps the pleco to survive.
Can you post water test results for ammonia, nitrite, nitrate, and pH? If you remove the shark, add live plants, and go easy on other foods, there is no reason we can't help you get this tank cycled with just the pleco, which I would highly suggest. The tank will cycle easier and quicker this way, which means safer for the fish.
Oh, and check the phosphate levels in both your tank and your tap water, and post those too, please. The hair algae you described is usually from phosphate problems. If that's what it turns out to be and it's in your tap water too, there are easy ways to eliminate it. Also, make sure your light is not on for more than 10 - 12 hrs/day.
We'll do what we can to help.

 

[bettababy]

I have to agree with Joe on this one... no more than once/day for feeding. A fish needs time to digest what you feed it. My fish eat every other day, unless I'm feeding fry or seahorses. The amount you feed each day should be completely consumed within 1 - 2 minutes. Anything longer than that and it begins to breakdown and pollute water. The gravel vac would only pick up the waste you could still see...
Sorry Blue, but your feeding schedule sounds a bit excessive to me. That could lead anyone, but especially a beginner into big problems with your schedule what it was listed.
I will agree with Blue about moving the shark asap, though. It's not just a size issue you'll be dealing with for the shark. They are aggressive, territorial, and sensitive to water quality. If they feel invaded, they will attack other fish, even and especially corys, who occupy the same territory in the tank. I currently have 1 rainbow shark, about 4 inches long now, and he has a 40 gallon planted tank all to himself for those reasons. Anything else that goes into that tank soon disappears. While the red tail and rainbow sharks don't grow quite as fast as some of the others, they still grow at a rapid rate.
For safety of all concerned, I'd move it as soon as possible.

 

[bettababy]

If you're planning to build your own tank, I would suggest getting some help from someone with first hand experience. This is not the easiest thing to pull off, and depending on size/shape, it will need to be braced specifically for that. 1 - 2 cm thick isn't all that thick when it's holding something like water. For a tank the size you will need to keep the shark, it's going to need to be thicker plexiglass than that. Then there is bonding and sealing the tank, also not so easy unless you've got help from someone with experience. The risks you take in doing it on your own are big, because that's a lot of water to leak or come crashing through the side of a tank. Water damage could be really bad. That also means the safety of the fish is at risk. I call your idea "playing with fire" unless you have experienced help.