Why did they put chlorine in your well?
Chlorine should come out after a few days but you might want to test it before using it in an aquarium. Or add a dechlorinator to any well water used in the tank for a couple of weeks.
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Never buy fish if the shop is doing a water change or has done a water change in the last couple of days. The fish suffer stress when they get a water change and if you take the fish straight after it has had a water change, and put it into a new tank with new water, it will stress even more.
Try to find out when the shop does water changes and buy the fish the day before they do the water change. You want the leave the fish in the shop tank for at least 3 or 4 days (preferably more) after they do a water change so it recovers from the stress.
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The fish in the picture looks a bit stressed, probably from being in a white container. The white reflects the light and stresses the fish. this is probably why it was swimming fine at night but sits on the bottom during the day.
These fish come from black water, which is dark tea stained water and it is not very bright.
If the container is on the ground, it will also stress the fish when someone walks past because there is no surface cover to hide under. Young Arowana are eaten by lots of birds and without something to hide under, it will stress.
You can put plastic or real water lilies or floating plants in the container and that will shade it and make the fish feel more comfortable.
Put a thin layer of brown or black gravel on the bottom so the light doesn't reflect around and stress the fish.
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TURNING LIGHTS ON AND OFF
Stress from tank lights coming on when the room is dark can be an issue. Fish don't have eyelids and don't tolerate going from complete dark to bright light (or vice versa) instantly.
In the morning open the curtains or turn the room light on at least 30 minutes (or more) before turning the tank light on. This will reduce the stress on the fish and they won't go from a dark tank to a bright tank instantly.
At night turn the room light on and then turn the tank light off. Wait at least 30 minutes (or more) before turning the room light out. This allows the fish to settle down for the night instead of going from a brightly lit tank to complete darkness instantly.
Try to have the lights on at the same time each day.
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Also he said "look at his tail curled in, thats a sing of a healthy arowana" is it true?
Normally fish curl their tail if they are stressed, sick or have some type of infection around the tail. Healthy fish don't normally curl their tail.
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i know they are great jumper so i have covered the tank with a steel net.
Use stainless steel or plastic/ nylon netting. Stainless steel won't rust. Plastic or nylon netting is less likely to damage the fish if it jumps, whereas steel could scratch it.
