Rainbow shark rubbing against fake plants

Question
QUESTION: Hi,

I am new to owning a rainbow shark (Rambo).  Yesterday I noticed that my shark was rubbing up against the rocks and fake plants...Im not sure if that is like a personality characteristic  of rainbow sharks.  Also, when he rubbed against the fake plants some kinda white stringy substance started floating up in the water. I don't see any white spots on his body, and I'm' not sure if he is sick.  Im not sure if treating him with ICH if he does not have it will harm him.  
He is in a 5 gallon tank and is about a little past an inch long.  I do know my Ph is good, and i use water conditioner that kills nitrate and ammonia. When i got him the fish store person said 5 gallons was just enough for him with no other fish he said they need about 1 gallon per inch of a fish, but if you can help me with my situation I would really appreciate it, i really want to act fast if something is wrong.  Thanks.


Sabrina

ANSWER: Hello Sabrina,
Unfortunately, scratching against rocks and decor is a sign of parasites. I would use some anti-parasitic medicine, and make sure you do plenty of water changes.
If you didn't get him that long ago, I would return him. Instead you could get something like a kuhli loach, or a cory cat. A five gallon tank is not large enough for your current fish.
The one inch of fish per gallon rule has many flaws, and really only works for small, skinny-bodied fish - such as neon tetras or guppies. You may want to upgrade to either a ten gallon tank, or exchange him for a smaller fish. Especially since he is sick.
The thing you have to remember is that fish come from all over the world, and have all different kinds of water - not just salt water and freshwater, but different levels of salinity, alkalinity, and pH. They come from well oxygenated water and not so oxygenated water, dark water with a lot of hiding places, and clear water with no places to hide.
Also, some are aggressive, and territorial. Your albino rainbow shark (which is actually a kind of loach) is territorial, and fairly aggressive. He needs a lot of room to claim for his own, and a 5 gallon tank will not do. Just like some people would not do well living in a room the size of a closet, he needs room to swim and roam.
I would recommend looking up some important tips and advice on fish keeping, one of the most important being fish compatibility, and the nitrogen cycle.
Best of luck to you.

---------- FOLLOW-UP ----------

QUESTION: Hi Brittany,

Thanks a lot for your help, I will definitely upgrade to a 10 gallon tank.  Should I treat the tank for ICH?  I heard that is a type of parasite, or just a parasite medication in general?

Thanks again,
Sabrina

Answer
Sabrina,
If he has Ich you should be able to see it on him. They resemble white dots, or sometimes grains of salt. This may or may not be Ich, but usually any anti-parasitic medicated food or meds such as Lifegaurd that are an all in one can help combat an illness when you're not 100 percent sure what it is.