I love my marbled goby. They are very tough fish. Until they get past 4-5", they are susceptible to fungus, after that they are one of the hardiest fish I have ever owned. They get much larger than what that website suggests. The true max size is 24", more likely they will stay smaller but if given proper care they should not have any trouble getting past the 8-10" that the website claims. At about 18 months old, mine is already 9". My buddy has one that is close to 18" but I dont know how old. They readily take most foods and pellet training is fairly simple. They do get lazy when they get larger, but young ones can be fairly active for ambush predators.
I just want to add that they readily accept most foods if trained young. If you neglect training them until they get older, you will have a hard time feeding them anything other than live/frozen foods. Mine readily accepts shrimp pellets and massivore however. Ive seen a few different personalities where they only accept smelt/silverside and others that will eat so well that they sometimes die from eating things they shouldnt...also, dont trust them with anything. I have seen one die from eating a lima shovelnose that was not much smaller than itself...they are not as aggressive as RTC but the appetite is there