irridescent sharks

Question
I recently set up a 55 gallon aquarium. I had 5 tiger barbs, 1 pleco, and two
wood shrimp from a ten gallon tank that I moved into the 55 gallon aquarium
and added some live plants. I wanted to add some other fish and a few
sharks. I was told that iridescent sharks would be good and also some larger
tetras. However I have researched alot now about the iridescent sharks
because they seem extremely unhappy. They play dead when anyone goes
into the room. I never see them eat anything or do anything except play dead.
They will be swimming around until anyone walks in and immideately they jet
into a wall and then play dead. I feel bad and worry that they are not eating. I
have been doing 20-30% water changes twice a week for the last two weeks
and nothing has seemed to improve. I alternate feeding bloodworms and
flake food. Is there anything I can do to make the irridescent sharks more
active and happy (there are three really small ones- approximately 8cm).
Any suggestions would be great.
Thanks

Answer
Hi Mike,
They will always have a tendency to spook very easily and crash into the aquarium sides. It seems also that they like to play      whenever they get scared no matter what you do. It could also be because they are still very young and this might improve some with age. I think as they get older and larger they won't play       as much but it is always possible that they will ram into the sides of the tank if they get scared. I have had other fish such as tinfoil barbs that would get scared and crash no matter what I did. You will usually read that you have to place plants on the ends of the aquarium and in other areas of the aquarium to try to prevent this but it never did work for me. It seems that certain types of fish always have a problem with movement in the room  causing them to get scared and crash. I've lost fish before from them crashing so hard into the sides that they injured themselves permanently. I don't think that your sharks are really unhappy. It's just the personality that irridescent sharks have.
Here is a website that other people have described as the same problem that you are having.
http://www.aquahobby.com/gallery/e_pang.php

Hope this has helped,
Karen