wait on the goby until yourtank has matured more form the LR;most of time you will get hitch hiker pods from the LR;but if you add goby too soon, it will consume all the pods before they have reached a sustainable population; shuld only take 4-8 months depending; you should be able to tell if you havce large enough pod pop when you see them on the LR, the glass, the substrate,possibly free swimming; you CAN add cleaner shrimp NOW; they will benefit your fish, but sometimes will be too agressive toward cleaning them;they will also SCAVENGE for food you put in;same w/ the crabs, most crabs are scavengers or hunters;they do not neccesarrily selectively feed on algae; that is not what their mandibles are designed for