Even though the neon goby is known for cleaning, they are rather small and are skittish when it comes to large fish. There's also the potential of them being sucked down overflows and getting lost in large tanks. Cleaner shrimps get lazy fast... and in my experience become more annoying than beneficial. I don't think those blennies mentioned are cleaners either.
Those are certainly concerns - screening off your drains, and maybe your top too, is usually a good idea when keeping small fish - but I wouldn't say hiding or being skittish are the most common behaviors in neons, even when in larger tanks with bigger fish. Generally, as a cleaner, it is in their nature to be pretty bold around fish. I have see then clean too, but it not often. (Rarely called for is my guess.)
My main viewing experience of them is in a ~250 gallon display setting....lots of rock, plenty of space for them to spread out (or hide forever if they wanted.) Tangs from ~7" down to ~4", including unicorns, surgeonfish and bristletooth...wrasses including melanurus, mystery and yellow "coris" and the biggest baddest six-line I've ever seen. LOL. He was twice the size of the mystery! Anyway, I know this is anecdote too, but even among all those large-ish, high-energy fish the pair of neons in this tank seemed to be out 80-90% of the time - often on the mantle of a clam chillin - rarely together. Seemed relaxed and natural to me though.
I can imagine if one had them cramped up into a smaller tank or a tank that was more overstocked that there could be issues with aggression and territoriality, jumping, hiding, etc....true of any fish that gets crammed into too small a space though.
I can also imagine them "disappearing" into any tank that has a serpent or brittle starfish. :behindsofa:
Skunk cleaner shrimp can get spoiled on food if the tank is overfed or they get too much fish food and they can be shy if there's too much flow....but they should be one of the most out-and-about cleaner shrimp. Trying to maintain any shrimp along with coral or anemones that are going to be slowly eating chunky foods on a regular basis is going to be an exercise - shrimps are voracious scavengers when properly motivated.
Blennies were just there for "cool stand-in" status....similar shape, nice stripes, better survivability. But the fang blennies are probably more likely to defend themselves (namesake defense) or run away if a big fish approaches...doubtful to see any cleaning. (But hey...even tangs are known to clean
sometimes...who knows!)
My $0.02.
-Matt
