I have a 55 g w/ 1 oscar 1 geen terror, 1 blood, 1 shark and one Robusta botia - http://animal-world.com/encyclo/fresh/loaches/Loach.htm. The oscar ate the smaller Robusta which i think was sick, so now I am thinking of returning the other loach to the pet store before it gets eattened. What loach can I get for my aquarium or will the Robusta be okay by itself?