I bought a new Kubotai loach today he's about 1 1/2" long. I have two yoyo's that are about 4" and two other Kubotais that are about 3". They are in a 30gal and i was wondering if i should be concerned about aggression towards the smaller loach? I don't really have any experience adding smaller loaches, I got all four of the other ones within a week of each other. Any input would be appreciated.