royal plecos are pretty but will outgrow a 29. might take a while but they get big. im also not sure if theyre the most durable of plecos. i just had mine die from a small ick outbreak in the tank. i cured everyone else of it but he just couldnt shake the ick.
try clown plecos, zebra plecos, king tiger plecos, peppermint plecos, snowballs, butterfly plecos.
ive been looking at plecos alot lately to replace the royal that dies. got a queen arabesque today and its a very pretty fish.
look at planet catfish, lots of pleco info and pictures there.
like was mentioned alot of plecos arent the best algae munchers. if your looking to clean algae id say a few ottos and a handfull of amano shrimp would do the job and the shrimp are neat to watch jet around. plus those are alot cheaper than the flashy plecos.