Wow thats cheap, they cost about £250 ($500) over here.
Zebras should only be kept by experienced aquarist as they are very rare and tricky to look after and you wouldn't want to lose a fish costing that much.
I can guess Panaque maccus are a little territorial and can drive out plenty of fish from its boundaries. Plenty of plecos are territorial. They're best kept in a long tank where they can establish territories well enough for other fish to avoid.