I find my MTS also like the marimo balls. Be sure to pull the balls out once in awhile and give them a squeeze out, as they tend to collect debris inside the ball.
And if you plan to have Otos, best to allow some algae to grow for them to eat. They are pretty much obligate algae eaters. Many of them will not eat man made foods, and subsist on biofilm if there's no algae. I actually grow algae on rocks outside the tank, in the brightest light I have, and drop them in for them to clean up, and then put back in the algae farm to grow more.
They're not so much delicate as they are reliant on gut bacteria to digest their algae. After they are caught [ using cyanide to stun them], they starve 'til they get to your tank, unless the store has a tank with algae in it for them, which pretty much never happens. They don't even recognize algae tabs as being edible in many cases.. they've come from rivers full of real algae ! So their gut flora die off and they can appear to be full of food when in fact they are starving, due to lack of bacteria to digest what they did eat.
The advice to buy them after they've been in a store for awhile is excellent.. the weakest will have died by then, sadly enough. Drip acclimation is good too.
Generally, if they live two months in your tank, they will live for years. But many of them do not make it past the two month mark. Only the strongest of them survive. It's a shame, they are such charming little guys.