Oscar And Blue Lights

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I bought some clamp lights for my next tank and while I was at Home Depot, I bought a 13w blue light for moonlight effect to see how it goes.  I'm testing it right now in my 75 gallon oscar tank and after I turned it on the oscar went straight to the sand and now he's hanging out on the other half of the tank where its still dark.
 
Will it take time for him to get used to the blue light or should I just not use one on their tank?  This is more of an experiement before I get more lights to replace my t8 fixtures in my 125 and 75g tanks