red tail shark

I've got a 4 inch red tail with a 6 inch red devil he holds his own, and they seem to not bother each other cause they have their own space.
 
I have a 3 inch rainbow in my 25 gal and she (I think) has her own space under a peice of slate but she often gets chased by my rubberlip pleco who has become really really territorial for some reason....
 
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