My husband has bought a Blue Shark from LFS. They say it will grow to about 8 inches but they seemed lacking with knowledge about feeding etc. My husband said he thought it was some sought of catfish. It is blueish/grey on top and has a white underneath. It does have small whiskers and is about 3 inches long at present. All it seems to want to do is swim against the glass at the front of the tank. It isn't agressive but it justs keeps swimming head up and tail towards the bottom of the tank against the glass. Is this normal 
